Biotronik CYLOS Cylos DR-T User Manual ENG Cylos 352923 0 102 rev 2

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Table of Contents
Table of Contents .......................................................... 1
Introduction ................................................................... 8
NBG Code.................................................. 11
Programmer and Software........................... 11
Indications and Contraindications.............................12
Indications for Closed Loop Stimulation ........ 12
General Indications..................................... 13
General Contraindications............................ 14
Home Monitoring ........................................................16
Introduction............................................... 16
Types of Implant Messages.......................... 18
Home Monitoring Parameters ...................... 19
Criteria for the Use of Home Monitoring .........20
Pacing Types – Modes ................................................22
Closed Loop M odes ...................................22
Rate-Adaptive Modes....................................22
Overdrive Modes..........................................23
DDD Mode ..................................................23
DDI Mode ...................................................26
DVI Mode....................................................27
VDD Mode ..................................................27
AAI Mode, VVI Mode.....................................28
AOO M ode, VOO Mode..................................28
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2
DOO Mode ..................................................28
Triggered Pacing .........................................29
DDT/A Mode, DDT/V Mode...........................29
VDI Mode....................................................30
OFF Mode...................................................30
Magnet Effect ..............................................30
Summary of the Functions and Timing Intervals
of the Modes ...............................................32
Timing Functions ........................................................34
Basic Rate ..................................................34
Rate Hysteresis ...........................................34
Repetitive Rate Hysteresis ............................35
Scan Rate Hysteresis ...................................36
Night Program ............................................38
Refractory Period.........................................39
Dynamic AV Delay........................................40
AV Hysteresis ............................................. 41
AV Repetitive Hysteresis ...............................42
AV Scan Hysteresis ......................................42
Negative AV Hysteresis.................................43
Sense Compensation....................................44
Blanking Period...........................................44
Safety AV Delay ...........................................45
Pacing When Exposed to Interference.............46
Pacing and Sensing Functions...................................49
Pulse Amplitude and Pulse Width ..................49
Sensitivity...................................................49

3
Lead Configuration ......................................50
Continuous Measurement and Recording of Lead
Impedance..................................................50
Automatic Lead Check................................. 51
Amplitude Control (ACC)...............................52
ACC Status .................................................57
Lead Detection and Auto-Initialization ............58
Antitachycardia Functions..........................................63
Upper Tracking Rate ....................................63
Tachycardia Mode .......................................64
Tachycardia Behavior...................................66
2:1 Lock-in Management ..............................69
PMT Management....................................... 71
Preventive Overdrive Pacing..........................74
VES Lock-in Protection .................................77
Rate Adaptation ..........................................................78
Accelerometer-Based Rate Adaptation ......78
Physiologic Rate Adaptation (The CLS
Feature) ....................................................79
Individually Adjusting CLS Parameters..... 81
The CLS Safety Feature .............................82
Automatic Initialization of Closed Loop
Stimulation ...............................................82
Sensor Gain ................................................83
Automatic Sensor Gain.................................84
Sensor Threshold.........................................85
Rate Increase..............................................86

4
Maximum Activity Rate.................................87
Rate Decrease.............................................87
Sensor Simulation .......................................88
Rate Fading – Rate Smoothing ......................89
IEGM Recordings.........................................................92
Types of IEGM Recordings ............................93
Diagnostic Memory Functions (Statistics)................96
Overview.....................................................96
Interrogating and/or Starting Statistics ..........97
Timing Statistics .........................................98
Arrhythmia Statistics .................................101
Sensor Statistics .......................................107
Sensing Statistics ......................................108
Pacing Statistics........................................109
Follow-up Options .....................................................111
Realtime IEGM Transmission with Markers ...111
IEGM Recordings .......................................112
Analog Telemetry of Battery, Pulse and Lead
Data.........................................................113
Rate and Sensor Trend...............................114
High-Resolution Threshold Test ...................114
P/R-Wave Test ..........................................115
Retrograde Conduction Test........................115
External Pulse Control (NIPS)......................115
Temporary Program Activation....................116
Patient Data M emory .................................118
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5
Storing Follow-up Data ...............................118
Position Indicator for the Programming Wand
...............................................................118
Handling and Implantation ......................................119
Sterilization and Storage ............................119
Opening the Sterile Container......................120
Connecting the Leads.................................120
Follow-up Basics .......................................................124
Battery Status ...........................................124
Testing the Pacing Threshold......................125
Sensing Functions .....................................126
Retrograde Conduction...............................126
Rate Adaptation.........................................127
Sensor Gain ..............................................128
Sensor Threshold.......................................128
Battery, Pulse and Lead Data......................129
Replacement Indication............................................130
Expected Time Until ERI .............................130
Remaining Service Time after ERI................132
Cautionary Notes ......................................................133
Medical Complications ...............................133
Technical Malfunctioning............................133
Muscle Potentials ......................................133
Electromagnetic Interference (EMI)..............134
Risky Therapeutic and Diagnostic Procedures
...............................................................136
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6
Explantation..............................................141
Technical Data ..........................................................142
Pacing Modes ...........................................142
Home Monitoring — Programmable Parameters
...............................................................142
Home Monitoring – Non-Programmable
Parameters/Value Ranges ..........................142
Pulse and Timing Parameters .....................144
Rate Adaptation.........................................150
Parameters at Replacement Indication.........151
Additional Functions ..................................152
Default Programs ......................................153
Materials in Contact with Human Tissue.......157
Programmer .............................................157
Electrical Data...........................................158
Battery .....................................................158
Service Times............................................158
Mechanical Data........................................159
Storage Conditions ....................................159
X-ray Identification.....................................159
Projected Tolerances of Factory Settings ......160
Product Line .............................................161
Block Diagram for Cylos DR........................162
Block Diagram for Cylos DR-T .....................163
Block Diagram for Cylos VR ........................164
Federal Communications Commissin Disclosure .......165
Terms and Abbreviations............................................166
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7
Index...........................................................................170

8
Introduction
Introduction
Cylos is a line of pacemakers that may be used for all indications of
bradycardic arrhythmias. There are three pacemakers in the Cylos
product group. There are single- and dual-chamber pacemakers that
achieve physiological rate adaptation using Closed Loop Stimulation,1
and a third pacemaker that permits external monitoring via a Home
Monitoring feature.2
The myocardium contracts differently under different states of load.
Closed Loop Stimulation (CLS) uses these variations to provide the
patient with a physiologic pacing rate that is specific to his or her
needs. The dynamics of the cardiac contractions are evaluated by
unipolarly measuring the intracardiac ventricular impedance. Changes
in the impedance curves over time are directly proportional to the state
of load. By evaluating these changes, the pacemaker then sets the
pacing rate. Closed Loop Stimulation uses ventricular sense (V S) and
ventricular pace (V P) events in calculating the pacing rate.
A traditional accelerometer is another way Cylos can adapt the pacing
rate. With the accelerometer, which is integrated into the hybrid
circuit, any patient movement generates an electrical signal. This
signal is used as input for controlling how the pacing rate is adapted.
Cylos DR
The dual-chamber pacemaker has separate atrial and ventricular leads
and is suited for patients who need AV-synchronous pacing.
Cylos VR
The single-chamber pacemaker needs just one lead and is only suited
for ventricular pacing.
Cylos DR-T
Cylos DR-T features the complete functionality of Cylos DR and is also
equipped with the Home Monitoring function. For more information,
please see the "Home Monitoring" section.
Pacing in a closed loop.
An extended telemetry option available in Cylos DR-T

9
Introduction
All the systems have extensive features that allow quick diagnosis and
delivery of safe therapy for cases of bradycardic arrhythmia. The
guided follow-up functions have been largely automated. Initialization
and optimization of Closed Loop Stimulation is also automated. This
saves the physician time and eliminates problems in verifying and
adjusting the pacemaker.
Even during implantation, the implant can detect any connected leads
– one of the key aspects of Auto-initialization.
Cylos features numerous special functions:
• The amplitude control function (which is referred to as ACC, Active
Capture Control) continuously monitors the effectiveness of
ventricular pacing and continuously adjusts the pacing amplitude to
the pacing threshold.
• Closed Loop Stimulation (CLS) is automatically initiated and
optimized.
• Statistics tracking intrinsic AV conduction help optimize the
programmed AV delay and AV hysteresis.
• Antitachycardia functions provide the patient significant protection
from the consequences of tachycardias. Automatic mode conversion
or automatic mode switching prevent atrial-controlled pacing in the
case of atrial tachycardias.
• A preventive overdrive mode reduces the occurrence of atrial
tachycardias by using minimal overdrive pacing of the patient’s
intrinsic rate.
• Extensive algorithms help to prevent, recognize, and terminate
tachycardia induced by the pacemaker.

10
Introduction
• Innovative rate hysteresis promotes the patient’s own cardiac
rhythm and avoids unnecessary overdrive pacing.
• AV hysteresis features support intrinsic conduction and hence the
natural contraction process.
• The night program adjusts the pacing rate to the reduced metabolic
needs of the patient while resting at night.
• The regular automatic lead impedance check triggers the switch
from a bipolar to unipolar pacing mode when values outside the
normal range occur.
• Automatic sensor features make it easier to adjust pacemaker
parameters to the individual needs of the patient.
• The Rate Fading function ensures that the heart rate does not drop
abruptly when the intrinsic rate suddenly decreases. Rather, the
rate is gradually reduced until the basic or sensor rate has been
reached.
• IEGM recordings provide insight into the events before a
tachycardic phase.
• Extensive memory functions (such as the histogram, rate trend,
activity chart, etc.) facilitate evaluation of the state of the patient
and the pacemaker.
• Atrial and ventricular extrasystoles as well as atrial tachycardias can
be analyzed and classified with respect to their complexity and
when they occur.
• An external pulse control function is available for terminating atrial
tachycardias and for use during electrophysiologic studies. Burst
stimulation, with realtime control of the burst rate, and
programmed stimulation, with up to 4 extrastimuli, are available.

11
Introduction
• Automatic functions and the storage of follow-up data in the implant
simplify and accelerate the follow-up process.
Note:
This technical manual describes all the features of
the Cylos line of pacemakers.
A special note of any features that apply only to
specific Cylos models will be made in the text or
margins.
NBG Code
DDDR is the NBG code1 for Cylos DR/DR-T:
Pacing in both chambers
Sensing in both chambers
Inhibition and triggering of pulses
Rate adaptation
VVIR is the NBG code2 for Cylos V R:
Pacing in the ventricle
Sensing in the ventricle
Inhibition and triggering of pulses
Rate adaptation
Programmer and Software
The pacemakers can only be programmed with appropriate
BIOTRONIK programmers, e.g., ICS 3000 or PMS 1000, along with the
current software version. The range of functions and available
parameters depend on the software module being used. Therefore, the
operation and availability of certain functions can differ from the
description in this manual. Specific information pertaining to the
programmable options is provided in the user manual of the respective
software module.
See Bernstein et al., The Revised NASPE/BPEG Generic Code for Antibradycardia,
Adaptive-Rate, and Multisite Pacing. PACE 2002, Vol. 25, No. 2: 260-264
See Bernstein et al., The Revised NASPE/BPEG Generic Code for Antibradycardia,
Adaptive-Rate, and Multisite Pacing. PACE 2002, Vol. 25, No. 2: 260-264

12
Indications and Contraindications
Indications and Contraindications
Indications for Closed Loop Stimulation
Closed Loop Stimulation uses ventricular sense (Vs) and ventricular
pace (Vp) events in calculating the pacing rate. The indications for
Closed Loop Stimulation are summarized in the following:
—
Patients with intermittent AV conduction disorders or intact AV
conduction. The algorithm is based on an AV hysteresis that can
be turned off for patients with high-degree AV blocks.
—
Patients with a permanent AV block can be paced in the ventricle
with the required V P parameter set to “yes”.
—
Patients with vasovagal syncope can be optimally supported with
the programmable “dynamic runaway protection” parameter.
—
Patients who would benefit from a constant AV delay are better
treated when the “CLS dynamics” parameter is turned off.
The following information includes general indications and
contraindications for the use of cardiac pacemakers. Please refer to
the appropriate medical literature for detailed information. The
guidelines of the American College of Cardiology (ACC),1 the American
Heart Association (AHA), and the German Society for Cardiology and
Cardiovascular Research2 are particularly good sources of information.
Guidelines for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices,
Gregoratos et al., ACC/AHA Task Force Report, Circulation 2002; 106: 2145-2151,
October 15, 2002
Richtlinien zur Herzschrittmachertherapie; Indikationen, Systemwahl, Nachkontrolle.
[Guidelines for Cardiac Pacemaker Therapy; Indications, System Selection, Follow-up
Care]. Reports by the Commission for Clinical Cardiology at the German Society for
Cardiology - Cardiovascular Research] (DGK), B. Lemke, W. Fischer, H. K. Schulten,
Steinkopff Verlag 1996

13
Indications and Contraindications
General Indications
The following conditions are regarded as general indications for
pacemaker implantation when they occur together with symptoms such
as syncope, dizziness, reduced physical capacity, or disorientation:
• Sinus node arrest and symptomatic bradycardia with or without an
AV conduction disorder.
• Intermittent or complete AV block.
• Brady-/tachycardia syndrome or other symptoms of sick sinus
syndrome that result in symptomatic bradycardia.
• Supraventricular reentry tachycardias that can be suppressed by
chronic AV-sequential pacing.
• Atrial and ventricular ectopic arrhythmias that can be suppressed
by permanent AV-sequential pacing.
In contrast to a single-chamber pacemaker, a dual-chamber
pacemaker is indicated for patients who require increased cardiac
output. This includes active patients and patients who have
experienced, or are likely to experience, pacemaker syndrome.
An atrial-controlled dual-chamber mode (DDD and VDD) is indicated
for patients who have an intact spontaneous atrial rhythm. Ventricularcontrolled, AV-sequential dual-chamber pacing modes (DDI, DVI and
VDI) are indicated for patients in whom ventricular pulse triggering due
to spontaneous atrial events is not required or desired. Rate-adaptive
pacing is indicated for patients who exhibit chronotropic incompetence
and require increased pacing rates with physical activity.

14
Indications and Contraindications
The functions "Automatic Mode Conversion" and "Mode Switching" in
connection with the pacing modes DDD(R) and VDD(R) are useful in
cases of paroxysmal atrial tachyarrhythmia to interrupt any atrial
synchronization of ventricular pulses during the phases of atrial
tachyarrhythmia. The DDD(R) mode with Mode Conversion is an
alternative to the DDI(R) or DVI(R) mode in this case.
The AAI mode is indicated in the presence of symptomatic sinus node
dysfunction as long as adequate AV conduction exists. The VVI mode is
indicated in cases of symptomatic bradycardia when there is no
(longer) significant atrial contribution to hemodynamics.
The demand modes as well as the asynchronous DOO, AOO, and VOO
modes (with reduced sensing functions) are indicated in cases of
medical/technical complications (e.g., electromagnetic interference,
sensing errors, lead fractures, detection of myopotentials, muscle
stimulation, etc.).
The triggered pacing modes DDT, DDI/T, VDT, DV T, AA T, and VV T as
well as the VDI and OFF modes are indicated for diagnostic purposes.
General Contraindications
There are no known contraindications for the use of
multiprogrammable and multifunctional dual-chamber pacemakers,
provided that implantation is preceded by an adequate diagnosis, and
no parameter combinations inappropriate for the patient’s condition
are programmed. In individual cases, it is recommended that the
tolerance and effectiveness of parameter combinations are checked by
observing the patient for some time after programming. The following
are contraindicated:
• Operating modes with atrial control (DDD, VDD, AAI) are
contraindicated in the presence of chronic atrial tachycardia as well
as chronic atrial fibrillation or flutter.

15
Indications and Contraindications
• If slow retrograde conduction is encountered after ventricular
pacing, a longer atrial refractory period and/or a shorter AV delay
may have to be programmed to prevent pacemaker-mediated
tachycardia. Programming DDI, DVI, or VVI modes is rarely required
in these instances.
• If elevated rates above the basic rate are not well tolerated by the
patient (e.g., the patient has chest pain as a result), a low “upper
rate” and lower “maximum sensor rate” should be programmed. In
these cases, atrial-controlled modes and rate-adaptive modes may
even be contraindicated.
• If a case of pacemaker syndrome has been observed or is likely to
develop, the modes VDD, VVI and VOO are contraindicated. The DDI
mode is contraindicated in cases of pacemaker syndrome where
sinus rates are above the basic rate.
• Atrial single-chamber pacing is contraindicated in the presence of
existing AV conduction disorders or if failing AV conduction can be
demonstrated by suitable tests.
• In the presence of competing spontaneous rhythms, modes without
sensing and inhibition ability in the chamber affected are
contraindicated.
• Unipolar pacing is contraindicated for patients who also have an
implanted cardioverter-defibrillator (ICD). There is a risk of ICD
inhibition or accidental delivery of pacemaker pulses.
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16
Home Monitoring
Home Monitoring
Introduction
Cylos DR-T
With BIOTRONIK's Home Monitoring function, patients can be treated
even more effectively. All Home Monitoring implants are equipped with
a small transmitter and are designated by the letter "T," e.g., Cylos DRT and Lumos DR-T.
The Home Monitoring function has no effect on any functions and
features of the basic implant, such as pacing and sensing functions,
preset parameters, or memory functions.
With Home Monitoring, you as the physician can view the data
transmitted by the implant in a comprehensive report called a Cardio
Report, allowing you to always be informed about your patient's
cardiac status.
A patient device receives messages from the implant and transmits
them to the BIOTRONIK Service Center. At the Center, the data are
processed and are made available to you via a secure Internet
connection.
The implant’s Home Monitoring function can be used for the entire
operational life of the implant or for shorter periods, just a few weeks
or months.
The most important components of Home Monitoring are the implant,
the patient device, and the BIOTRONIK Service Center.
The Implant
The power of the implant's transmitter is very low, so that the patient's
health is not affected in any way. The resulting short transmission
range requires the use of a special patient device to forward the
implant data to the BIOTRONIK Service Center.

17
Home Monitoring
The patient's implant data are sent to the patient device at regular
intervals. With Home Monitoring, the distance between the implant and
the patient device should not be less than 20 centimeters (8 inches)
and not more than two meters (6 feet).
The implant can send three different types of messages: trend
messages, event messages and patient messages (for pacemakers
only). For more information about the message types, see "Types of
Implant Messages," on page 17.
Patient Device
The RUC or CardioMessenger® patient device works similarly to a
cellular phone and transmits the messages received from the implant
as short messages (SMS) to the BIOTRONIK Service Center via the
cellular phone network. The integrated batteries enable batteryoperated usage for 15-24 hours, depending on the model. The patient
device can, of course, also be used with the included charging station.
BIOTRONIK
Service Center
At the BIOTRONIK Service Center, the implant messages transmitted
by the patient device are processed and then made available to you via
the Internet or a fax in the form of a concise report called the Cardio
Report.
Cardio Report
In the Cardio Report, the transmitted implant data are displayed in
graphs and tables. With the online option, you can individually
configure the Cardio Report graphs for each patient. For certain events,
the Cardio Reports are also sent to you by fax, e-mail, or SMS, in
addition to being available for viewing on the Internet.
The title of the Cardio Report indicates the report type. There are three
types of Cardio Reports:
• Trend reports
• Event reports
• Patient reports (for pacemakers only)
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18
Home Monitoring
On event reports, the title tells you which event triggered that Cardio
Report, e.g., Event report – ERI detected.
Programmer
You must set up the Home Monitoring function in the programmer and
register with the BIOTRONIK Customer Service Center.
For more information about activating Home Monitoring on the
programmer, see the manual of your programmer.
For information about signing up for Home Monitoring, see the manual
for the BIOTRONIK Home Monitoring® Service.
Types of Implant Messages
Implants with the Home Monitoring function send implant messages at
set times or when certain events have occurred. Message transmission
can be triggered as follows:
• Trend message –
every day, at a certain time, the message is triggered
• Event message –
an event triggers the message
• Patient message –
the pacemaker patient triggers the message with a special magnet
Trend Message
Using the programmer, you decide the time at which the daily implant
message is transmitted to the patient device. It is recommended that a
time be chosen during which the patient is sleeping because the
patient will then be close to the patient device.
The length of the time interval (the monitoring interval) is not
programmable: it is preset to "daily." For each monitoring interval, a
data set is generated in the implant and the transmission is triggered.

19
Home Monitoring
Event M essage
When the implant detects certain cardiac and technical events, an
event message is sent to the patient device. For each implant, you
decide what kinds of events will trigger a message. You can go to the
Home Monitoring Service Center on the Internet and configure whether
you also want to receive event reports for these events.
Certain events, e.g., when the battery reaches ERI, can never be
omitted. You can find more information about events in the online help
section for the Home Monitoring Service Center.
Patient Message
Pacemaker patients can apply a special magnet over the pacemaker
and trigger a message. Please provide your patient with comprehensive
information about how to handle the magnet and for which physical
symptoms you consider it appropriate for your patient to trigger a
message.
Caution!
The special magnet may only be distributed to
pacemaker patients.
A patient-triggered message does not affect any trend message
transmission settings.
For more information about programmer settings with the patient
message, see the manual of your programmer.
Home Monitoring Parameters
Home Monitoring
Off, On
You can activate (ON) or deactivate (OFF) the Home Monitoring
function with your programmer. Any other partial functions can only be
used if Home Monitoring has been previously activated.

20
Home Monitoring
Monitoring Interval
1 day
When you activate the Home Monitoring function, the (daily) interval of
the trend message transmission is automatically activated.
Transmission Time
of the Periodic Report
Between 0:00 (12:00 a.m.) and 23:50 (11:50 p.m.)
For the trend message, program a time between 0:00 (12:00 a.m.) and
23:50 (11:50 p.m.). Selecting a time between 0:00 (12:00 a.m.) and
4:00 (4:00 a.m.) is recommended as that is a time when the patient is
usually asleep.
Event Message
Off, On
The implant detects certain cardiac and technical events that trigger
an automatic message transmission. As a default setting, this option is
activated.
Patient Message
Off, On
The patient-triggered message can also be programmed. This option is
not activated for the default settings.
Criteria for the Use of Home Monitoring
Intended Use
The fundamental medical objective is to make diagnostic information
available to physicians. The therapeutic effect of implants that transmit
data is not affected because the Home Monitoring Service Center has
no direct effect on the implant.
For a specific description of the objective of the Home Monitoring
system, see the manual for the BIOTRONIK Home Monitoring® Service.

21
Home Monitoring
Prerequisites
The technical prerequisites for access to Cardio Reports are described
in the manual for the BIOTRONIK Home Monitoring® Service.
Indications and Contraindications
The known indications and contraindications for pacemakers and ICDs
are applicable regardless of Home Monitoring. There is no absolute
indication for the use of the Home Monitoring Service Center.
There are no contraindications for the use of the Home Monitoring
Service Center as a diagnostic tool, because it has no effect on the
diagnostic or therapeutic functionality of the implant. However, proper
use of Home Monitoring requires the complete cooperation of the
patient. Moreover, a prerequisite is that the physician has access to
the Home Monitoring data (per fax and/or Internet) in order to be able
to use the Home Monitoring Service Center.
Warnings and Precautions
The known warnings and precautions for pacemakers and ICDs are
applicable regardless of Home Monitoring. However, there are specific
precautions for Home Monitoring.
Please observe the specific warnings and precautions for Home
Monitoring in the manual of the BIOTRONIK Home Monitoring® Service
and in the manual of the patient device.

22
Pacing Types – Modes
Pacing Types – Modes
Closed Loop M odes
Valid for Cylos DR and
Cylos VR
Cylos achieves physiologic rate adaptation using Closed Loop
Stimulation. Closed Loop Modes work the same way as non-rateadaptive modes. The only difference is that the basic rate is increased
when Cylos senses that the patient is under stress. Closed Loop modes
are identified by the designation "CLS."
In the DDD-CLS and VVI-CLS modes, the atrial and/or ventricular
refractory period can cover a larger portion of the basic interval with
high closed loop pacing rates. As a result, the sensing of spontaneous
events may be prevented or impossible.
Rate-Adaptive Modes
Valid for
Cylos DR-T
Rate-adaptive modes are marked by an "R" (for "rate") in the pacemaker
code. Rate-adaptive modes function identically to corresponding nonrate-adaptive modes, with the exception that the basic rate increases
when patient exertion is detected by the motion sensor. The non-rateadaptive modes are described below. In rate-responsive demand
modes (DDDR, DDTR/A, DDTR/V, DDIR, DVIR, VDDR, VVIR, AAIR), it is
possible that the atrial or ventricular refractory period can comprise a
major portion of the basic interval at high sensor-modulated rates. As a
result, sensing of intrinsic actions is limited or completely suspended.
For more information, see the "Rate Adaptation" section.

23
Pacing Types – Modes
Overdrive Modes
Overdrive modes reduce the probability of atrial tachycardias. In this
case, the pacing rate always lies slightly above the intrinsic atrial heart
rate. Preventive overdrive is available in modes DDD(R)+, DDT/(R)A+,
DDT/V(R)+, AAI(R)+ and AAT(R)+. For a detailed functional
description, see the "Preventive Overdrive Pacing" section.
DDD Mode
In the DDD mode, the basic interval starts with an atrial sense (A S) or
atrial pace event (A p) or a ventricular sense event not preceded by an
atrial event (VES = "ventricular extrasystole"). If no atrial sense event
occurs within the basic interval, atrial pacing takes place at the end of
the basic interval (See Figure 1), and the basic interval is restarted.

24
Pacing Types – Modes
Figure 1: AV-sequential pacing in DDD mode without an intrinsic event
In the case of an atrial sensed or paced event, the AV delay starts
together with the basic interval. If a ventricular sensed event does not
occur within the AV delay, ventricular pacing is triggered at the end of
the AV delay. If ventricular sensing (V S) occurs within the AV delay, the
ventricular pulse delivery (VP) is inhibited.
Figure 2: An atrial sensed event restarts the basic interval
If atrial sensing occurs, atrial pacing is inhibited and the basic interval
is restarted (See Figure 2).

25
Pacing Types – Modes
Figure 3 and Table 1 summarize the timing intervals initiated by
sensing or pacing. The table distinguishes between pacing at the end
of the AV delay (VP) or pacing at the end of the AV safety delay (V SP)
and between sensing within the AV delay (V S) or sensing outside the AV
delay (VES).
Figure 3: Start of timing intervals in the DDD mode depending on the events
that occur
Timing Interval
Basic Interval (DDD)
Event
Ap
As
•
•
Basic Interval (DDI)
Atrial Refractory Period
Vp
Vs
VES
•
•
•
Vsp
•
•
•
•
•
Atrial Refractory Period Extension
•
Upper Tracking Rate Interval
•
•
•
•
Ventricular Refractory Period
•
•
•
•
Table 1: Timing intervals initiated by pace and sense events in DDD and DDI
modes (Vsp = ventricular safety pacing)

26
Pacing Types – Modes
Timing Interval
Event
Ap
As
(Dynamic) AV Delay
•
•
AV Safety Delay
•
Interference Interval (A)
Vp
Vsp
Vs
VES
•
•
•
Interference Interval (V)
Blanking Period (A)
•
•
•
Blanking Period (V)
•
•
•
Table 1: Timing intervals initiated by pace and sense events in DDD and DDI
modes (Vsp = ventricular safety pacing)
DDI Mode
In contrast to the DDD mode, the basic interval in the DDI mode does
not start with a P wave, but rather with ventricular sensed or paced
events. The VA interval is started together with the basic interval. If no
atrial or ventricular sensing occurs within the VA interval, atrial pacing
takes place at the end of the VA interval (See Figure 4).
Figure 4: AV-sequential pacing in DDI mode without an intrinsic event
Upon pacing, the AV delay is restarted. If sensing occurs, atrial pacing
is inhibited (See Figure 5). The AV delay does not start with this sense
event, but again at the end of the VA interval. Thus, P waves in DDI
mode do not trigger ventricular events.

27
Pacing Types – Modes
Figure 5: Inhibition of atrial pacing in DDI mode by an atrial sensed event
occurring within the VA interval. The atrial refractory period restarts at the
end of the VA interval.
DVI Mode
The DVI mode is based on the DDI mode. In contrast to the latter,
atrial sensing does not occur in DVI mode. Therefore, atrial pacing is
forced at the end of the VA delay. Ventricular sensing within the VA
interval inhibits both the atrial and the ventricular pulse. Ventricular
sensing within the AV delay inhibits the ventricular pulse.
VDD Mode
The VDD mode is derived from the DDD mode. In contrast to the latter,
no atrial pacing takes place. Therefore, the basic interval starts at an
atrial sense event, a ventricular extrasystole, or at the end of the
preceding basic interval if no sense event occurs.
To prevent pacemaker-mediated reentry tachycardia, the atrial
refractory period is also started by ventricular paced events that were
not triggered by atrial sensed events (See Figure 6).

28
Pacing Types – Modes
Figure 6: Prevention of pacemaker-mediated tachycardia in VDD mode
AAI Mode, VVI Mode
The AAI and VVI single-chamber pacing modes are used for atrial or
ventricular demand pacing. In each case, pacing and sensing only
occur in either the atrium (AAI) or the ventricle (VVI).
The basic interval is started by a sense or pace event. If there is a
sense event before the end of the basic interval, pulse delivery is
inhibited. Otherwise, pacing takes place at the end of the basic
interval.
AOO Mode, VOO Mode
In these pacing modes, pulses are emitted asynchronously in the
atrium (AOO) or ventricle (VOO). When using VOO or AOO mode, the
risks associated with asynchronous ventricular pacing must be
considered.
DOO Mode
Asynchronous AV-sequential pulses are delivered in this pacing mode.
When using DOO mode, the risks associated with asynchronous
ventricular pacing must be considered.

29
Pacing Types – Modes
Triggered Pacing
Triggered pacing modes correspond to the respective demand modes,
the difference being that detection of an atrial/ventricular event
outside the refractory period does not cause pulse inhibition, but
rather triggers immediate pulse delivery to the respective chamber.
The corresponding pacing modes are:
Demand:
DDD
VDD
DDI
DVI
AAI
VVI
Triggered:
DDT
DDT/A
DDT/V
VDT
DDI/T
DVT
AAT
VVT
However, the following differences do occur: There is no AV safety
delay in the DDT, DDI/T and DV T pacing modes. It is not necessary
since ventricular pulse inhibition because of crosstalk (ventricular
sensing of the atrial pacing pulse) cannot occur in these modes.
In the DDI/T and DV T pacing modes, the basic interval is not restarted
if ventricular sensing occurs within the AV delay.
DDT/A Mode, DDT/V Mode
The DDT/A and DDT/V modes are derived from the DDT mode. In
DDT/A mode, the pacemaker delivers a pulse in the atrium after every
sensed atrial event and inhibits pacing in the ventricle if required.
Similarly, in DDT/V mode, an immediate pulse in the ventricle, and if
required pulse inhibition in the atrium, follows every sensed ventricular
event.

30
Pacing Types – Modes
VDI Mode
The VDI mode is derived from the VVI mode. In contrast to the latter,
the VDI mode allows intra-atrial events to be recorded. The timing
corresponds to the VVI mode, however. The VDI mode is designed for
measuring retrograde conduction with the IEGM and/or the marker
function. Retrograde conduction time can be determined directly on
the programmer, or on an additional ECG recorder, as the length of
time between a ventricular pace or sense event and the subsequent
atrial sense event.
OFF Mode
In the OFF mode, pacing pulses are not delivered, except when used
with external pulse control. Without external pulse control, the OFF
mode is used for detection and morphological evaluation of the
intrinsic rhythm. With external pulse control, the OFF mode is used for
electrophysiologic studies and to combat tachycardia. The OFF mode
is only programmable as a temporary program. The pulse and control
parameters remain adjustable in the OFF mode. With the use of the
external pulse control function, the programmer triggers pacing pulses
and sensed events can be transmitted to the programmer. Note that
sensing is limited by the refractory period, whereas pacing is not.
Magnet Effect
Placing a magnet (or the programming wand) over the pacemaker
causes the built-in magnetic switch in the pacemaker to close. The
pacemaker response to magnet application is adjustable.
Note:

The following functions are deactivated by magnet
application:
31
—
—
—
—
—
—
—
—
—
—
Pacing Types – Modes
Recording of statistics
Mode switching
Automatic lead check
AV hysteresis and rate hysteresis
Rate adaptation
Overdrive
PMT protection
VES lock-in termination
Active capture control (ACC)
Rate fading
Automatic Magnet Effect
During the first 10 cycles after magnet application the pacemaker
paces asynchronously at 90 ppm (at 80 ppm upon reaching the
replacement indication). Thereafter, synchronous pacing at the
programmed basic rate occurs (or at the night rate, if one has been
programmed). During asynchronous pacing, the AV delay is reduced to
100 ms if a longer interval was programmed. This avoids ventricular
fusion beats when AV conduction is intact and makes it easier to detect
the effectiveness or ineffectiveness of ventricular pacing.
Asynchronous Magnet Effect
The sensing function of the pacemaker is deactivated for the duration
of the external magnet application. During this time, the pacemaker
paces asynchronously at 90 ppm (at 80 ppm upon reaching the
replacement indication).
Synchronous Magnet Effect
The sensing and pacing behavior of the pacemaker remains unchanged
when a magnet is placed over the pacemaker. The basic rate also
remains intact (except after the replacement indication has been
reached). The synchronous magnet effect is only important for the
follow-up and if you want IEGM recordings to be triggered by the
patient. This guarantees that the sensing function remains enabled
when the programming wand or magnet is applied, and that the
replacement indication can be monitored.

32
Pacing Types – Modes
Summary of the Functions and Timing Intervals
of the Modes
Table 2 summarizes the functions and time intervals that apply to the
various demand pacing modes. Not included are rate-adaptive
parameters and parameters that can be programmed in all pacing
modes.
The sensitivity can always be programmed during pulse inhibition
and/or pulse triggering.
•
Rate hysteresis
•
•
•
•
Repetitive rate
hysteresis
•
•
•
Scan rate hysteresis
•
•
Upper tracking rate
•
A pulse
duration/ amplitude
VVT
•
VVI
•
AAT
DVI
•
AAI
DDI/T
•
VDI
DDI
•
VDT
DDT/V
•
VDD
DDT/A
Basic rate
DVT
DDT
Pacing Modes
DDD
Parameter
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
V pulse
duration/ amplitude
•
•
•
•
•
•
•
•
As inhibits Ap
•
•
•
As triggers Ap
As triggers Vp
•
Vs inhibits Vp
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Dynamic AV delay
•
•
•
•
AV hysteresis
•
•
•
AV repetitive
hysteresis
•
•
•
•
•
•
•
V refractory period
•
•
•
A refractory period
•
•
•
•
•
•
•
•
•
Table 2: Functions and timing intervals of the different pacing modes

•
•
•
•
•
•
•
•
•
Vs triggers Vp
•
•
•
Pacing Types – Modes
AV scan hysteresis
•
AV safety delay
•
Sense compensation
•
V blanking period
•
Wenckebach
possible
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Table 2: Functions and timing intervals of the different pacing modes
• = present
A = atrium, atrial
V = ventricle, ventricular
A p = atrial pace event
As = atrial sense event
Vp = ventricular pace event
Vs = ventricular sense event

VVT
VVI
AAT
AAI
VDI
VDT
VDD
DVT
DVI
DDI/T
DDI
DDT/V
DDT/A
Pacing Modes
DDD
Parameter
DDT
33
34
Timing Functions
Timing Functions
Basic Rate
The basic rate is the rate at which the pacemaker delivers pulses in the
absence of a spontaneous rhythm or if sensing is deactivated. The
corresponding interval is called the "basic interval" - the interval
between two pacing pulses.
In the atrial-controlled modes, the basic interval is started by an atrial
event. In the atrial-controlled dual-chamber modes, the basic interval is
also started by a ventricular extrasystole.
In the ventricular-controlled modes, the basic rate is started by a
ventricular event.
Rate Hysteresis
To preserve a spontaneous rhythm once it occurs, a rate hysteresis can
be programmed in the modes DDD(R), DDT(R), DDT(R)/A, DDT(R)/V,
DDI(R), VDD(R), VDT(R), VDI(R), VVI(R), VV T(R), AAI(R) and AA T(R). In
this case, the pacemaker, after detecting a sense event, “waits” not
only for the duration of the basic interval for a new sense event, but
also for the duration of the longer hysteresis interval before pacing
occurs. This means that the pacemaker tolerates a spontaneous
rhythm whose rate lies below the basic rate. However, the intrinsic rate
must be higher than the rate that corresponds to the hysteresis
interval. If a sensed event does not occur within the hysteresis interval,
a pacing pulse is delivered at the end of the hysteresis interval. The
next interval then conforms to that of the basic rate or the interval
determined by the sensor (See Figure 7).

35
Timing Functions
Figure 7: Basic rate and rate hysteresis in DDD mode
In pacing modes DDD(R), DDT(R)/A, DDT(R)/V, DDT(R), VDD(R),
VDT(R), AAT(R), and AAI(R) the hysteresis interval starts with an atrial
sense event. In the modes DDI(R), VVI(R), VVT(R) and VDI(R) it starts
with a ventricular sense event. In modes DDD(R), DDT(R)/A, DDT(R)/V,
DDT(R), VDD(R) and VDT(R) it also starts with a ventricular
extrasystole.
The rate hysteresis is specified as the difference from the basic rate. In
rate-adaptive pacing, the hysteresis remains constant while the
hysteresis rate follows the variable (sensor-controlled) basic rate.
Note:
If the rate hysteresis is to be used in the DDI
mode, the AV delay must be programmed shorter
than the spontaneous conduction time. Otherwise,
the pacemaker paces at the hysteresis rate instead
of the basic rate even in the absence of
spontaneous activity.
Repetitive Rate Hysteresis
The repetitive rate hysteresis helps to maintain the spontaneous
rhythm and avoid unnecessary pacing in situations that exceed the
basic hysteresis, such as post-extrasystolic pauses.
If such a pause occurs, the pacemaker continues to pace at the
hysteresis rate for a programmable number of cycles instead of
immediately reverting to the basic rate (See Figure 8).

36
Timing Functions
Figure 8: Repetitive rate hysteresis
An existing spontaneous rhythm is thus once again able to inhibit the
pacemaker. This prevents any worsening of the hemodynamics, as
might otherwise occur in modes such as VVI pacing. The pacemaker
supports and stabilizes the spontaneous atrial rhythm in DDD or DDDR
modes. This prevents the undesirable suppression of the spontaneous
rhythm through overdrive, especially during periods of rest. Repetitive
rate hysteresis is only activated in the presence of a stable intrinsic
rhythm, that is, when continuous inhibition by the spontaneous rhythm
has occurred during the previous 180 cycles, at the very least.
Scan Rate Hysteresis
The scan rate hysteresis promotes a spontaneous rhythm during longer
phases of pacing.

37
Timing Functions
If scan hysteresis is activated, the pacemaker will reduce the pacing
rate temporarily to the hysteresis rate after every 180 consecutive
atrial paced events. The number of scan intervals can be programmed
(See Figure 9).
Figure 9: Scan rate hysteresis
If no intrinsic event is detected during the scan intervals, pacing at the
basic rate is resumed (at the sensor rate in rate-adaptive mode).
Scanning for a spontaneous rhythm is repeated after an additional 180
cycles.
Reaction to Vasovagal Syncopes and Carotid Sinus Syndrome
The scan rate hysteresis can be used in conjunction with the repetitive
rate hysteresis to treat patients with vasovagal syncopes and carotid
sinus syndrome of a primarily cardioinhibitory type. The following
programming is recommended for this purpose.
Basic rate
Increased value, for example 90 ppm
Rate hysteresis
Such that the hysteresis rate at rest is always lower
than the intrinsic rhythm (e.g., -50)
Scan rate hysteresis Enabled, with the number of cycles set according to
the patient's condition
Repetitive rate
hysteresis

Enabled, with a low number of cycles
38
Timing Functions
Basic Rate:
Increased value, for example 90 ppm
Rate Hysteresis:
Such that the hysteresis rate at rest is always lower than the intrinsic
rhythm (e.g., -50)
Scan Rate Hysteresis:
Enabled, with the number of cycles set according to the patient's
condition
Repetitive rate
hysteresis
Enabled, with a low number of cycles
This programming will inhibit the pacemaker until bradycardia
episodes occur. If the rate drops due to an event, the pacemaker will
pace at the hysteresis rate for the set number of repetition cycles (the
confirmation period). The pacemaker will switch to the higher
intervention rate to prevent possible syncope only if a spontaneous
rhythm does not occur during the confirmation period, which should be
set as short as possible. The pacemaker will scan for a spontaneous
rhythm every 180 cycles (scan rate hysteresis) to avoid long pacing
phases. If the attack has been terminated by that time, the pacemaker
will be inhibited; otherwise, it will repeat the scan every 180 cycles.
Note:
These patients should only be treated with a
DDD(R) system to exploit the contribution of the
atrium to ventricular filling and to overall
hemodynamics as much as possible during such
attacks.
Night Program
When the night program is activated, the pacemaker reduces its
activity during the night. This makes it possible to adapt the pacing
rate to the patient's reduced metabolic needs during this time.
Furthermore, VVI and VOO pacing may prevent the possible worsening
of hemodynamics.

39
Timing Functions
The beginning and end of the night, as well as the basic night rate, can
be programmed. At the beginning of the night period, the basic rate
and the hysteresis rate are gradually reduced to the night values. If
rate adaptation is enabled, the sensor threshold during the night is
increased by one increment (less sensitive). This prevents undesirable
rate increases – even in patients who do not sleep soundly. After the
night has ended, the pacemaker resumes its daytime pacing values.
Note:
Please take into consideration that the patient may
travel to other time zones. If this is expected, the
night duration should be programmed accordingly
shorter or even deactivated.
Note:
The internal clock of the pacemaker is
automatically adjusted to the clock of the
programmer at every follow-up. Ensure that the
time displayed by the programmer is correct.
Refractory Period
Sensed events that occur during the refractory period do not affect the
timing. The functions related to tachycardia behavior are an exception:
automatic mode conversion and mode switching. In these functions,
sensed events within the refractory period are utilized for arrhythmia
detection.
In DDD(R) and VDD(R) modes with automatic mode conversion, the
atrial refractory period (ARP) can be triggered, i.e., a sensed event
occurring in the atrial refractory period can restart it.
In the DDD mode the ARP not only starts after atrial sensing or pacing,
but also with ventricular extrasystoles (VES). This is to prevent
pacemaker-mediated tachycardia. For the same reason, the ARP also
begins in the VDD mode upon ventricular pacing that was not triggered
by an atrial event, and upon VES. In the DDI mode, the ARP starts only
after an atrial sensed or paced event.

40
Timing Functions
Dynamic AV Delay
Valid for Cylos DR and
Cylos DR-T
The AV delay defines the period of time between an atrial event and the
subsequent ventricular stimulus. The "dynamic" AV delay lets you
optimize the AV delay for five different atrial rate ranges. The AV delay
selected for this rate is then effective depending on the current atrial
rate (the A-A interval). The dynamic AV delay is valid after atrial
detection and after sensor-driven atrial pacing. The AV delay can be
individually set for the following rate ranges:
Basic rate, < 70 ppm, 70 – 90 ppm, 91 – 110 ppm, 111 – 130 ppm, >
130 ppm.
In the non-rate-adaptive modes, an AV delay may be separately
selected for AV-sequential pacing at the basic rate. The AV delays in
the four other atrial rate ranges are then only active after the
corresponding atrial sensing.
In addition to the option of setting the AV delay individually for these
ranges, the programmer also offers three settings (low, medium and
high). Refer to the table below for details. You can deactivate the
optimization feature and select fixed AV delays. In non-rate-adaptive
modes, the AV delay after atrial pace events is different from the AV
delay after atrial sense events.

41
Timing Functions
Rate range
AV delay (in ms) for
programming the dynamic AV
delay to
Low
Medium
High
Basic rate (for non- 180
rate-adaptive modes)
180
180
Less than 70 ppm
180
180
180
70 - 90 ppm
170
160
150
91 -110 ppm
160
140
120
111 - 130 ppm
150
120
100
Over 130 ppm
140
100
75
Table 3: Dynamic AV delays
The dynamic AV delay serves to prevent pacemaker-mediated
tachycardias and supraventricular tachycardias. See also the
"Antitachycardia Functions" section.
AV Hysteresis
An AV hysteresis can be programmed to a low, medium or high setting
to promote intrinsic AV conduction. With AV hysteresis active, the AV
delay is extended by a defined time period after sensing an intrinsic
ventricular event. The long AV interval remains intact as long as an
intrinsic ventricular activity is measured during the extended AV delay.
The short AV delay interval without extension by the hysteresis value
follows after ventricular pacing.
Caution!

If AV hysteresis is enabled along with the algorithm
for detecting and terminating pacemaker-mediated
tachycardias (PMT Management), the variations in
the AV delay for detection and termination of a
PMT have priority over any possible simultaneous
activation of the AV hysteresis.
42
Timing Functions
AV Repetitive Hysteresis
In AV repetitive hysteresis, the AV delay is also extended by the defined
hysteresis value after the sensing of an intrinsic ventricular event. In
contrast to normal AV hysteresis, once the ventricular pace event
occurs, the long AV delay remains intact for a programmed number of
cycles. If intrinsic activity occurs during one of these repetitive cycles,
the long AV delay remains intact. Only once the repetitive cycles have
elapsed without any instances of spontaneous AV conduction does the
pacemaker switch back to the short AV delay. The AV repetitive
hysteresis hence reduces pacing when existing intrinsic activity is
suppressed by occasional pace events within the extended AV delay.
AV Scan Hysteresis
In AV scan hysteresis, 180 consecutive cycles are observed and if there
were only paced events and no spontaneous ventricular activity, the AV
delay is extended by the additional AV hysteresis interval. The long AV
delay remains intact for a pre-defined number of cycles. If spontaneous
AV conduction occurs within the defined number of cycles, the AV
hysteresis remains intact. The short AV delay interval resumes only
when no ventricular event has been detected within the defined number
of cycles and instead every one of these cycles ends with a pace. The
cycle counter once again begins counting the consecutive cycles in
which there was pacing. Intrinsic ventricular events (excluding VES)
reset the counter to zero. AV scan hysteresis hence reduces pacing in
situations in which intrinsic conduction exists but does not fall within
the defined AV delay.

43
Timing Functions
Negative AV Hysteresis
Purpose
In individual cases it can be necessary to promote ventricular pacing
and allow the least possible amount of conductions of the atrial sinus
rhythm. This can be especially necessary for patients with hypertrophic
obstructive cardiomyopathy (HOCM).
Description
With a sensed ventricular event (Vs), the function decreases the AV
delay and thereby promotes ventricular pacing. With a conventional
positive AV hysteresis, in contrast, the AV delay is increased to support
sinus rhythms.
Negative AV hysteresis is optional. It is possible to program the
negative AV hysteresis together with the negative AV repetitive
hysteresis. This ensures that the pacemaker paces with the shorter AV
delay for a programmable number of cycles when a sensed event
occurs.
The following table shows the correlation between the standard values
of the AV delay and the negative AV hysteresis:
AV Delays (Standard)
Negative AV Hysteresis
100
100
120
100
130
100
140
100
150
100
160
120
170
120
180
130
190
140
200
150
225
170
250
180
300
200
Table 4: Negative AV Hysteresis

44
Timing Functions
Sense Compensation
For hemodynamic reasons, it is desirable to maintain a constant period
between an atrial and a ventricular contraction and to adjust it to
physiologic conditions. To this end, sense compensation can be used
to shorten the AV delay after atrial sensing. You can program values of
-15 to -120 ms for the sense compensation. In this case, the AV delay
after atrial sensing is shorter than it would be following atrial pacing
according to the value you have set. The AV delay after atrial pacing
then corresponds to the programmed AV delay.
Blanking Period
Atrial Blanking Period
The atrial blanking period is started after a ventricular pace (see Figure
10). Atrial sensing does not occur during the atrial blanking period.
This prevents atrial sensing of ventricular pacing (a phenomenon
known as “crosstalk”).
Ventricular Blanking Period
The ventricular blanking period is started after an atrial pace (see
Figure 10). During the ventricular blanking period, ventricular sensing
does not occur. This prevents ventricular sensing of atrial pacing (a
phenomenon known as “crosstalk”).
Programmable Values
The following values can be programmed for the blanking periods:
• Ventricular blanking period from 16 to 72 ms
• Atrial blanking period from 32 to 72 ms

45
Timing Functions
Note:
It is recommended that the lowest possible values
be selected, so that ventricular/atrial sensing is
ensured for the period during which
ventricular/atrial intrinsic rhythm may occur.
Note:
It is also recommended that the selected values be
high enough to prevent undesired sensing of
pacing in the other chamber.
This is possible with high atrial/ventricular pulse
energies and/or high ventricular/atrial sensitivities.
The blanking period is automatically extended by one increment in
some combinations of pacing and sensing polarities in order to prevent
crosstalk. The programmer will indicate the amount by which the
blanking period has been extended.
Safety AV Delay
In the DDD(R), DDT(R)/A, DDT(R)/V, DDI(R) and DVI(R) pacing modes,
the safety AV delay is started with atrial pacing. If a ventricular sense
event occurs within the safety AV delay, the pacemaker paces in the
ventricle at the end of the interval (Vsp = ventricular safety pace). If the
AV delay is shorter than the safety AV delay, pacing occurs at the end
of the AV delay.
This prevents ventricular pulse inhibition due to ventricular sensing of
atrial pacing (which would be crosstalk). (See Figure 10).

46
Timing Functions
Figure 10: Ventricular blanking period and the AV safety delay
If AV sequential pacing is observed with an AV delay corresponding to
the AV safety delay, this may be evidence of ventricular crosstalk
(recognition of atrial pulse delivery). In order to avoid crosstalk, you
can define a lower atrial pulse energy, a lower ventricular sensitivity
(assigning it a higher numerical value), and/or a longer ventricular
blanking period.
Pacing When Exposed to Interference
The pacemaker is equipped with interference protection to protect the
patient against undesired inhibition by non-cardiac signals. An
“interference interval” is started at the same time as the refractory
period. The interference interval is similar to a refractory period of 125
ms that can be re-set. If an event is detected in one of the two
chambers during the interference interval, the interference interval is
restarted in the corresponding channel. If the detected rate exceeds
480/min (= 8 Hz), then the interference interval is continually
restarted, so that the channel remains refractory throughout the entire
basic interval. The pacemaker will then pace asynchronously at the
programmed basic rate in that particular chamber as long as the
interference persists (one example would be electrical or
electromagnetic interference). For further details, see the “Cautionary
Notes” section.

47
Timing Functions
Depending on whether interference is sensed in either the atrium or the
ventricle, the following pacing modes will be used for the duration of
the interference:
Mode
Interference During EMI in the
Atrium
Ventricle
Atrium and
ventricle
DDD-CLS
DVI-CLS
DAD-CLS
DOO(R)
DDD(R)(+)
DVI(R)
DAD(R)(+)
DOO(R)
DDI(R)
DVI(R)
DAI(R)
DOO(R)
DVI(R)
VDD(R)
DOO(R)
VVI(R)
VAT(R)
VVI-CLS
VOO(R)
VVI(R)
VOO(R)
VOO(R)
AAI(R)(+)
AOO(R)
DDT(R)
DVT(R)
DAT(R)(+)
DOO(R)
DDT(R)/A(+)
DVD(R)
DAT(R)(+)
DOO(R)
DDT(R)/V(+)
DVT(R)
DAD(R)
DOO(R)
DDI/T(R)
DVT(R)
DAT(R)
DOO(R)
DVT(R)
DOO(R)
VDT(R)
VVT(R)
VAT(R)
VOO(R)
VDI(R)
VVI(R)
VOO(R)
VOO(R)
VVT(R)
AAT(R)(+)
VOO(R)
AOO(R)
Table 5: Interference modes
Mode
Interference During EMI in the
Atrium
Ventricle
Atrium and
ventricle
DDD(R)
DVD(R)
DAD(R)
DOO(R)
DDI(R)
DVI(R)
DAI(R)
DOO(R)
DVI(R)
VDD(R)
DOO(R)
VVI(R)
VVI(R)
Table 6: Interference modes

VAT(R)
VOO(R)
VOO(R)
48
Mode
Timing Functions
Interference During EMI in the
Atrium
Ventricle
Atrium and
ventricle
AAI(R)
AOO(R)
DDT(R)
DVT(R)
DAT(R)
DOO(R)
DDT(R)/A
DVD(R)
DAT(R)
DOO(R)
DDT(R)/V
DVT(R)
DAD(R)
DOO(R)
DDI/T(R)
DVT(R)
DAT(R)
DOO(R)
DVT(R)
DOO(R)
VDT(R)
VVT(R)
VAT(R)
VOO(R)
VDI(R)
VVI(R)
VOO(R)
VOO(R)
VVT(R)
AAT(R)
VOO(R)
AOO(R)
Table 6: Interference modes

49
Pacing and Sensing Functions
Pacing and Sensing Functions
Pulse Amplitude and Pulse Width
In dual-chamber systems, the pulse amplitude and the pulse width are
independently programmable for the atrium and the ventricle.
The BIOTRONIK PAC ("Pulse Amplitude Control") system keeps all
pulse amplitudes below 8.4 V constant during the entire service time of
the pacemaker.
This means that the pacing safety margin is maintained even when the
battery voltage drops. The pulse widths also stay constant during the
entire service time of the pacemaker.
Note:
If a pulse amplitude of 7.2 V or higher is
programmed and high pacing rates are attained,
output amplitudes may differ from the
programmed values, as in this case the amplitude
control may not have enough time for an exact
adjustment.
Sensitivity
The "sensitivity" parameter is used to set the pacemaker's sensing
threshold for intracardiac signals. The lower you set the value to be,
the higher the sensitivity.
When the sensitivity is high, there is a risk of the pacemaker being
inhibited by interference signals.
If bipolar leads are used, this risk can be reduced by programming the
pacemaker for bipolar sensing. In the case of high ventricular
sensitivity values, particular attention should be paid to the possibility
of ventricular pacing being inhibited by the atrial pulse (a phenomenon
known as crosstalk). Please see the "Ventricular Blanking Period" and
"AV Safety Delay" sections for more information.
Note:

The sensitivity should be programmed to less than
0.5 mV only when sensing is bipolar.
50
Pacing and Sensing Functions
Lead Configuration
In a unipolar configuration, the negative pole (the cathode) is situated
in the heart, while the positive pole (the anode) is formed by the
housing of the pacemaker. In a bipolar configuration, both poles of the
leads are situated in the heart.
The pacemakers allow you to program separate lead polarities for
pacing and sensing.
Compared with bipolar pacing, unipolar pacing has the advantage of
being clearly identifiable on the surface ECG, and its energy
consumption is a bit lower. Because one pole is formed by the
pacemaker housing in this case, unipolar pacing at high pulse
amplitudes can occasionally result in muscle stimulation in this area.
Because of its lower susceptibility to interference signals, i.e., skeletal
myopotentials, bipolar sensing offers a much better “signal-to-noiseratio” than unipolar sensing. Therefore, you can program higher
sensitivities (which are expressed as lower numerical values).
Caution!
If a unipolar lead is used in one of the chambers,
that lead configuration has to be programmed to
“unipolar.” Otherwise entrance and/or exit block
will result.
Continuous Measurement and Recording of Lead
Impedance
Cylos implants are also able to continuously measure the existing lead
impedance and record it as a short-term or a long-term trend.

51
Pacing and Sensing Functions
To this end, up to 4 stimuli of 4.8 V are triggered every 1.5 hours in
order to be able to determine the impedance under defined conditions.
If an amplitude higher than 4.8 V is set, the measurement is conducted
with the preset amplitude. Impedances between 200-3000 Ohm are
considered.
Automatic Lead Check
When this function is activated, the lead impedance is automatically
measured with every pace. If the impedance values lie above or below
the limits for several consecutive measurements, the system
automatically switches from a bipolar to a unipolar lead configuration.
The event is stored in an impedance trend. In the case of unipolar
configuration and a measurement outside the limits, the automatic
lead check is deactivated. In both cases, a message is generated that
is displayed at the next follow-up when the pacemaker is interrogated.
The automatic lead check can be activated for both the atrium and the
ventricle. The selected mode must provide for pacing in the selected
chamber.

52
Pacing and Sensing Functions
Amplitude Control (ACC)
Purpose
The amplitude control function (Active Capture Control - ACC) does the
following:
• Continuously monitors for effective ventricular pacing
• Periodically determines the ventricular pacing threshold
• Verifies the stimulus response
The advantage for the patient is that pacing remains effective even
when there are changes in threshold. Because the pacing amplitude is
continuously being adjusted to the threshold, it is possible to optimally
configure the energy reserves of the pacemaker and thus ensure
reliable patient care.
The ACC function works for a ventricular rate of up to 100 bpm.
Note:
Leads that generate high polarization artifacts are
not suitable for ACC.
Description
The efficacy of a stimulus is monitored by a beat-to-beat algorithm,
and the pacing energy is continuously adapted in the case of pacing
threshold fluctuations. The ACC function features the following subfunctions:
• Signal analysis
• Automatic pacing threshold search
• Verification of the stimulus response
Signal Analysis
Purpose
This function analyzes the signal quality of the ventricular evoked
stimulus response (when the stimulus is effective) and the polarization
artifacts (when the stimulus is ineffective). The function ensures that
only “undisturbed” or appropriate signals are evaluated. The signal
analysis function works for ventricular rates of up to 100 bpm.

53
Pacing and Sensing Functions
Description
—
—
—
—
—
The device measures with a constant, maximum pacing
amplitude for a duration of 5 cycles. The AV delay is shortened to
50 ms after pace and to 15 ms after sense.
After another 5 cycles, a second pulse is delivered with the same
amplitude 100 ms after the effective pace. This pace reaches
refractory tissue and thus does not evoke a stimulus response.
This makes it possible to determine the sole polarization
artifacts of the lead.
The average signal from the 5 measurements is used to compare
the effectiveness of the pacing pulse (signal morphology) and to
classify it as effective or ineffective.
If the signal quality is classified as insufficient, then the
pacemaker temporarily and automatically switches to safety
pacing until a successful measurement can be conducted.
If insufficient signal quality is measured repeatedly, then the
function is deactivated and the pacemaker switches to
permanent safety pacing.
Automatic Pacing Threshold Search
Purpose
The pacing threshold search function enables the pacing threshold with
the resulting stimulus to be automatically determined.
Prerequisite
Only after the signal quality has been successfully checked can the
pacing threshold search and amplitude adjustment functions be
executed.
Description
The threshold is determined as follows:
—
After successful verification of the signal quality, the pacing
amplitude is incrementally decreased with every second pace.
The AV delay is shortened to 50 ms after pace and to 15 ms
after sense.

54
—
—
—
Pacing and Sensing Functions
The incremental decrease of the pacing amplitude continues
until loss of capture is measured (meaning the pace is
ineffective). The last effective pacing amplitude that is measured
is accepted and saved.
After the first ineffective pace is detected, either the AV delay
(for atrial-controlled pacing) or the basic rate (for ventricularcontrolled pacing) is changed with the subsequent pace.
If again no stimulus response is measured, the ineffectiveness of
the pacing is confirmed.
A safety pulse with maximum pulse width is delivered after every
ineffective ventricular pace. This produces continuously effective
pacing.
Verification of the Stimulus Response
Purpose
This function allows the pacing amplitude to be continuously verified.
Verification of the stimulus response is possible for a ventricular rate of
up to 110 bpm.
Description
The pacing effectiveness is verified after each ventricular stimulus.
—
When pacing is effective, any current settings are retained.
—
When pacing is ineffective, a safety pace with a higher level of
energy is delivered after 130 ms at the latest. This is done at the
same amplitude but a greater pulse width.
—
When a series of 3 consecutive ventricular paces – even after the
AV delay has been changed – does not produce effective pacing,
first the signal analysis function is started and a new threshold
search is executed.
—
If pacing continues to be ineffective, the pacing amplitude is
increased in order to secure effective pacing. Due to this
automatic amplitude control, it is possible to select a smaller
safety margin, which can produce lower energy consumption
with safe pacing.
—
After the monitoring interval has elapsed, the threshold search
function is automatically executed. The pacing amplitude is set
to the threshold value plus the safety margin.

55
Pacing and Sensing Functions
Pacing in Single-Chamber Pacemakers
In order to ensure pacing in single-chamber pacemakers during signal
analysis and threshold verification, the device paces at a rate that is 10
ppm higher than the intrinsic rate.
Programmable Parameters
Amplitude Control ACC
ON; OFF; A TM
The "minimum ventricular amplitude" and "maximum ventricular
amplitude" parameters prevent a certain value of the ventricular
amplitude from being exceeded or undershot.
Minimum Ventricular
Amplitude:
0.2...(0.1)...3.6...(0.1)...4.8 V
Maximum Ventricular
Amplitude
2.4; 3.6; 4.8 ; 6.4 V
The search period parameter determines the times or intervals during
which the signal quality is continuously verified and the automatic
threshold search is executed. Intervals or times can be alternately
selected.
Scan Period
Interval; Times of Day
Interval
0.1; 0.3; 1; 3; 6; 12; 24 hours
Times of Day:
1st / 2nd Time of Day
00:00 to 24:00 hours, min. time unit of 15 min
Safety pacing is carried out at the amplitude of the last-measured
pacing threshold plus the set safety margin or the programmed initial
amplitude. The largest value of the pacing threshold influences the
safety pacing.
Safety Margin:
0.3...(0.1)..1.2 V

56
Pacing and Sensing Functions
Options for the ACC Function
The following options are available for the amplitude control function:
Active capture control
(ACC)
ON; OFF; A TM
ON
This option activates all sub-functions: The pacing threshold is
monitored and recorded, and the pacing energy is continuously
adapted. This is done with the following:
—
Signal analysis
—
Automatic pacing threshold search
—
Verification of the stimulus response
ATM (Active
Threshold Monitoring)
Option
The threshold is monitored and recorded at programmable time
intervals. This is done with the following:
—
Signal analysis
—
Automatic pacing threshold search
Therefore, there is no continuous adaptation of the pacing amplitude.
OFF
This setting deactivates the entire amplitude control function.
Caution!

When selecting the ATM or OFF options, make sure
that a sufficient safety margin is selected when
setting the pacing amplitude since there is no
automatic tracking of the pacing amplitude for
these options.
57
Pacing and Sensing Functions
ACC Status
It is possible to display information via the status of the Active Capture
Control (ACC) function. The following statuses are possible:
—
OK
—
OFF; the following is displayed: "---------"
—
Deactivated
—
Unconfirmed
—
High pacing threshold
OK
Shows that the ACC and ATM functions are activated and operating
properly.
OFF
Shows that ACC and ATM have been deactivated by the user.
Deactivated
After a maximum of 25 activation attempts per day, the function is
switched off by the implant, and the "Deactivated" status is displayed.
The programmer's printout displays the reason for the deactivation:
—
Insufficient signal quality
—
Stimulus is frequently ineffective
—
Initial test was not successful
—
Implant is in ERI mode
Unconfirmed
This status is displayed after the ACC function has been activated by
the user. Subsequently, the signal analysis and pacing threshold
search sub-functions are started. While these functions are running,
the status "Unconfirmed" is displayed.
Note:
Re-interrogate the implant to confirm the status.
After the sub-functions have run successfully, "OK" is displayed. The
ACC function is working properly.
High pacing threshold
If the recorded pacing threshold is higher than the maximum ACC
amplitude you have set, it is not possible to conduct signal analysis or
measure the pacing threshold. In this case, the user will see – on the
programmer display – a message indicating the need to increase the
maximum ACC amplitude.

58
Pacing and Sensing Functions
Lead Detection and Auto-Initialization
Lead Detection
Purpose
The lead detection function allows the implant to recognize the
connected leads as early as during implantation. This is also the basis
for being able to activate the auto-initialization function.
When the connected leads have been successfully detected, the pacing
and sensing polarities are automatically set. This depends on the type
of leads connected (be they unipolar or bipolar). The pacemaker uses
the lead impedance as a basis for the automatic polarity setting.
The pacemaker goes through the following phases:
—
An initial lead detection
—
Lead polarity is recognized
—
Confirmation
The Initial Lead Detection
To detect a lead, the implant (depending on the type) provides unipolar
pacing both in the atrial and ventricular channel and measures the
impedance of each stimulus. If intrinsic events are detected, they
trigger a pulse in the same chamber in which the event was detected.
This mimics the pacing response of an implant in the DDT mode. If the
measured impedances lie within 200-3000 Ohm, the lead is considered
detected.
Recognizing Lead Polarity
After successful detection of the lead, the implant switches to bipolar
pacing. The impedance is also measured during pacing. If it lies
between 200-3000 Ohm, a bipolar lead is considered confirmed.

59
Pacing and Sensing Functions
If the impedance lies outside of this range, the implant switches to
unipolar pacing. A unipolar lead is then confirmed.
Any sense event occurring during the phase for recognizing lead
polarity triggers a stimulus in the same chamber. This allows the
impedance to be measured.
The Confirmation Phase
After successful lead detection and detection of the lead polarity, an
implantation confirmation time of 30 minutes is started. Upon each
stimulus, the prior detected status must be confirmed. If this occurs,
lead recognition is successfully concluded.
The pacing pulse is as a rule inhibited when there are intrinsic cardiac
events. If intrinsic cardiac events are detected during the confirmation
phase, a stimulus is triggered every 10 minutes in the atrium and
ventricle to determine the lead impedance.
If there is no confirmation of the prior detected status, the initial lead
detection is restarted.
Auto-Initialization
Purpose
A few implant functions are automatically activated by the autoinitialization function. A prerequisite is the successful detection and
confirmation of the connected leads (in both chambers in the case of
dual-chamber implants).

60
Pacing and Sensing Functions
select lead polarity
implantation confirmation 30
min.
activating functions
statistics
standby
threshold
monitoring
PMT
protection
Figure 11: Implant functions that are activated by auto-initialization
During auto-initialization, the implant activates the following functions:
—
Statistics
—
ATM (the threshold recording feature of the ACC function)
—
Mode switching
—
PMT management
—
Closed Loop Stimulation standby mode, meaning that the
function has been completely initialized and deactivated
Note:
If the implant parameters have been changed in
the factory program prior to implantation, the autoinitialization function can no longer be executed. In
this case, only the lead detection function can be
run. Exception: Patient data can always be
configured regardless of the auto-initialization
function.
Note:
The lead detection and auto-initialization functions
can be run in the ventricle only with singlechamber pacemakers.

61
Pacing and Sensing Functions
CLS Standby Mode
CLS Standby Mode is where, after auto-initialization, Closed Loop
Stimulation is fully installed but deactivated. When the implant is
interrogated for the first time, Closed Loop Stimulation can be
activated. The CLS Standby Mode entails the following:
—
Closed Loop Stimulation has been installed, but is deactivated.
—
Until CLS is activated, the implant will pace at the basic rate.
—
During the first implant interrogation, the user can activate
Closed Loop Stimulation.
CLS is activated
Activating CLS after the first interrogation means the following
parameters have been set:
—
DDD-CLS mode for dual-chamber implants or VVI-CLS mode for
single-chamber implants.
—
AV delays and AV hystereses are automatically optimized for
CLS.
CLS is not activated
When Closed Loop Stimulation has not been activated after the first
follow-up, the following parameters are automatically set:
—
DDD mode for dual-chamber implants or VVI mode for singlechamber implants.
—
The AV delays from the factory program are activated. AV
hystereses are turned off.
Programmable Parameters
In addition to activating and deactivating the entire function, the subfunctions of lead detection can be activated individually.
Note:

Patient data can always be configured regardless
of the auto-initialization function.
62
Pacing and Sensing Functions
Note:
The auto-initialization function can only be
accessed before implantation. After the pacemaker
has been implanted and the auto-initialization
function has been run, this parameter is no longer
displayed on the Parameters screen.
Note:
If the implant is interrogated while autoinitialization is still running, the programmer will
show a message indicating this.
Auto-Initialization
ON; OFF; Lead Detection

63
Antitachycardia Functions
Antitachycardia Functions
Overview of antitachycardia functions:
• Upper tracking rate
• Tachycardia mode
• Tachycardia response
- mode conversion and
- mode switching
• PMT management
• Preventive overdrive pacing
• VES Lock-in Protection
Upper Tracking Rate
In atrial-controlled dual-chamber modes, the upper tracking rate, along
with the atrial refractory period, determines the maximum P-wavetriggered ventricular rate.
In all the triggered modes, the upper tracking rate limits the pacing
rate triggered by sense events.
Caution!

The upper tracking rate must be selected so that it
can be tolerated by the patient for an extended
period of time. The upper tracking rate determines
the minimum interval between a sense or pace
event and the subsequent atrial or ventricular pace
event. A decrease of the pacing interval to that of
the interval corresponding to the upper rate may
be initiated - also at rest - for example, by
detection of atrial extrasystoles, muscle potentials,
or other interferences. Therefore, programming a
low upper tracking rate may be indicated for
patients with increased vulnerability.
64
Antitachycardia Functions
Tachycardia Mode
The resulting tachycardia mode (either 2:1 or Wenckebach) is
automatically displayed, depending on the combination of selected
parameters.
A response similar to Wenckebach block (the WRL mode) results if the
selected upper tracking rate is lower than the rate corresponding to the
atrial refractory period. If the upper tracking rate is exceeded in the
WRL mode, the AV delay is continually prolonged so that the
ventricular pacing rate does not exceed the programmed upper
tracking rate.
Extension of the AV delay is interrupted as soon as a P wave occurs
before the end of the extended AV delay initiated by the preceding P
wave. In this case, the corresponding ventricular pulse is inhibited. If
the atrial rate is only slightly above the upper rate, then a 6:5 block, for
example, is the result.
Higher atrial rates produce higher degree blocks. If the length of the
atrial cycle eventually becomes shorter than the programmed atrial
refractory period, then a 2:1, 3:1, etc. block results.
Figure 12: Wenckebach-typical pacing behavior
If the selected upper tracking rate exceeds the rate corresponding to
the atrial refractory period, the maximum P-wave-triggered ventricular
rate results exclusively from the atrial refractory period, not from the
programmed upper tracking rate. If the length of the atrial cycle is
shorter than the programmed atrial refractory period, a 2:1 block, then
a 3:1 block, etc., will result before the upper tracking rate is reached in
the ventricle (DDD mode, 2:1 mode).

65
Antitachycardia Functions
The extended AV delay in the WRL mode and the associated
desynchronization of the atrium and ventricle increase the likelihood of
detecting retrograde P waves. This should especially be considered if
the dynamic AV delay is to be used for preventing or terminating
(pacemaker-mediated) reentry tachycardia, since the WRL mode
deactivates the dynamic AV delay when the upper rate is exceeded.
(See also PMT Management.)
If the spontaneous atrial cycle is shorter than the upper rate interval in
a rate-adaptive mode, the resulting pacing rate will depend on whether
the 2:1 rate has been exceeded or not. If this is the case, the
pacemaker will use the sensor rate as the pacing rate.
If the 2:1 rate is not exceeded, the pacemaker will use a rate that lies
between the sensor rate and the rate determined by the atrial
refractory period. In the latter case, the cycle length switches between
the sensor-defined interval and a shorter interval, which is at minimum
the length of the ARP. Response then depends on the ratio of the atrial
rate to the sensor rate and the atrial refractory period.
Minimum PVARP
This parameter enables the programming of a minimal value for the
PVARP and can be activated by the physician as an additional option.
When the parameter is activated, the respective PVARP value is
displayed on the programmer, approximately corresponding to the ARP
minus the highest possible value of the set dynamic AV delay.
In Wenckebach mode, the parameter can provide additional protection
against PMTs.

66
Antitachycardia Functions
Tachycardia Behavior
Cylos offers a choice of two algorithms that effectively suppress atrial
tachycardia from being conducted to the ventricle. At the start of a
tachycardic episode, the pacemaker automatically switches from an
atrial-controlled to a ventricular-controlled mode.
The following functions are available:
• Automatic Mode Conversion
• X/Z-out-of-8 Mode Switching
Automatic Mode Conversion
This option is available in the atrial modes DDD(R) and VDD(R) as well
as in DDT(R)/A and DDT(R)/V modes. In the case of atrial tachycardias
-- when the P-P interval is shorter than the ARP (the atrial refractory
period) – there is an automatic conversion to a mode without atrial
control. If the pacemaker is in DDD(R), DDT(R)/A, or DDT(R)/V mode,
it converts to DVI(R); if it is operating in VDD(R) mode, it converts to
VVI(R). This procedure prevents P-wave-triggered ventricular pacing
during tachycardia.
When mode conversion is disabled, an atrial sensed event within the
refractory period does not trigger an interval. In activated mode
conversion, however, an atrial sensed event within the refractory period
triggers a restart of the refractory period. The basic interval and the AV
delay are not restarted. If the coupling interval between the consecutive
P waves becomes shorter than the atrial refractory period, the atrial
refractory period will be continuously restarted. This means that the
pacemaker remains refractory in the atrium during the entire basic
interval (see Figure 13).

67
Antitachycardia Functions
Figure 13: In DDD mode without mode conversion (shown in upper graphic),
every second P wave triggers a ventricular pace during an atrial tachycardia.
In the DDD mode with mode conversion (shown in the lower graphic), an
atrial sensed event occurring in the atrial refractory period restarts the atrial
refractory period without the basic interval being restarted. This results in
DVI response for the duration of the atrial tachycardia.
This leads to non-P-wave-triggered AV-sequential pacing at the basic
rate for the duration of the atrial tachycardia. In DDD, DDT/A and
DDT/V modes, the pacemaker paces in the atrium and ventricle; in
VDD mode it paces only in the ventricle.
In rate-adaptive modes, the pacemaker paces at the sensor rate during
atrial tachycardia.

68
Antitachycardia Functions
Mode Switching with X/Z-out-of-8 Algorithm
This X/Z-out-of-8 algorithm can be used to program activation and
deactivation criteria. This prevents, for example, unnecessary mode
oscillations in the case of atrial extrasystoles or unstable atrial signals.
In addition, this algorithm can be employed to determine the speed at
which a de- and resynchronization of ventricular depolarization takes
place. This intervention rate can be programmed within a range from
100… (10)... 250 ppm.
The postventricular atrial blanking (PVAB) period after a ventricular
event can be programmed in a range from 50 – 200 ms. This prevents
any ventricular events from being registered in the atrial channel.
When an atrial tachycardia is detected, the pacemaker automatically
switches to a non-atrial-controlled mode: from DDD(R) to DDI(R), from
DDD(R)+ to DDI(R), or from VDD(R) to VDI(R) as well as from DDT(R)/A
and DDT(R)/V to DDI(R).
The mode switch can be programmed so that you can switch from a
non-rate-adaptive mode to a rate-adaptive mode, and vice versa. This
serves to prevent an undesirable rate drop to the basic rate in case of
physical stress.
An atrial tachycardia is considered sensed when the so-called X-out-of8 conversion criterion has been fulfilled. The X value can be
programmed in the value range (X = 3... (1)...8).
Detection is based on the continual evaluation of the last 8 atrial
intervals. When X out of 8 intervals reveal an atrial rate that lies above
the programmed intervention rate, then the conversion criterion is
fulfilled and mode switching automatically follows.
The pacemaker works in the programmed non-atrial mode until the
switch-off criterion (Z out of 8) has been fulfilled. The Z value can be
programmed in the value range (Z = 3... (1)...8). Likewise, the last 8
consecutive atrial intervals are continuously evaluated. When Z out of 8
intervals lie below the programmed intervention rate, the atrial
tachycardia is considered to be over, and the pacemaker automatically
switches to the originally programmed atrial-controlled mode.
The X or Z counter is reset to zero after every completed switching.

69
Antitachycardia Functions
Basic Rate during Mode Switching
It is possible to set a higher basic rate during mode switching, in order
to lessen undesirable hemodynamic conditions during mode switching.
This basic rate can be programmed to a higher value than the standard
basic rate, which leads to a slight increase of the cardiac output.
Programmable parameters:
Basic Rate during
Mode Switching
+5...(5)...+30 ppm
Note:
In the CLS modes, the Closed Loop rate is slowly
reduced to the sensor rate during mode switching.
If no rate-adaptive mode has been set for mode
switching, the CLS rate is slowly reduced to the
basic rate for during mode switching.
2:1 Lock-in Management
Description
When high atrial rates occur (such as during atrial flutter) in
conjunction with a relatively large AV delay, every other P wave may
regularly fall in the atrial far-field blanking (FFB) period. In this case,
the implant only detects half of the preceding atrial rate.

70
Antitachycardia Functions
The implant behavior thus resembles a 2:1 block. The implant paces in
the ventricle at a rate that corresponds to one-half of the atrial rate. At
very high atrial rates, this can produce high ventricular rates that are
physiologically unsuitable.
Example: If atrial flutter at a rate of 280 bpm takes place, then the
pacemaker paces with a ventricular rate of 140 ppm.
This phenomenon is called 2:1 lock-in and can cause the patient severe
problems in cases of long atrial flutter episodes.
Effects on Mode
Switching
In such a 2:1 situation, the Mode Switching function may not start at
all or only start at a very high rate, even though the function is
necessary. Therefore, the purpose of this function is to ensure the
effective use of mode switching.
To terminate 2:1 lock-in behavior, the AV delay is extended by a value
equal to the far-field blanking period, and the device may switch to a
ventricular-controlled pacing mode. The algorithms for the 2:1 lock-in
behavior have been designed as follows:
—
A phase where the behavior is suspected
—
Confirmation of such
—
Termination
When 2:1 Lock-In Behavior is Suspected
The following criteria must be fulfilled in order for there to be a 2:1
situation:
—
Eight (8) consecutive V pAs intervals must occur
—
The actual ventricular rate must be higher than 100 ppm
—
The average deviation of the 8 VpA s intervals must lie within the
tolerance limit of the 2:1 lock-in stability criterion
When these three conditions are met, the 2:1 lock-in situation is
considered confirmed.

71
Antitachycardia Functions
Confirmation of 2:1 Lock-In
Detection of a 2:1 situation is determined as follows:
—
The AV delay is lengthened for one cycle by a maximum of 300
ms, in order to confirm the 2:1 lock-in situation. In this manner,
events that previously fell within the blanking period are detected
by the implant as atrial refractory events. At the same time, the
minimum PVARP function is activated for the time of the AV
delay extension.
Termination
Termination is initiated as follows:
—
If the As-Ars interval attains the mode switch rate, the implant
immediately switches to the previously selected ventricular mode
(without first waiting for the criteria for X/Z-out-of-8 mode
switching).
—
If the rate that corresponds to the As-Ars interval is greater than
the mode switching rate, then the AV delay is reduced to the
current value in increments of 50 ms.
Programmable Parameters
The following parameter is displayed on Mode Switching screen, where
you can make the necessary settings.
2:1 Lock-in Protection
ON; OFF
PMT Management
The following features are provided for the prevention, detection, and
termination of pacemaker-mediated tachycardias (PMT):
PMT is prevented by
—
Restarting the basic interval and the atrial refractory period
—
Extending the atrial refractory period
PMT protection is offered by
—
PMT detection
—
PMT termination

72
Antitachycardia Functions
PMT Prevention
Pacemaker-mediated tachycardia is generally triggered by ventricle
depolarization that is out of synchrony with atrial depolarization, e.g.,
as would be the case in ventricular extrasystoles (VES). The
tachycardia is maintained retrogradely by VA conduction coming from
the ventricle depolarization due to pacing and antegradely by P-wavetriggered ventricular pacing.
In order to prevent PMT in cases where there is ventricular sensing
without a preceding atrial event, the pacemakers restart the basic
interval and the atrial refractory period (ARP). If an atrial refractory
period extension has been programmed, this is additionally prolonged
even further after a VES. A retrograde P wave with a VA conduction
time shorter than the ARP cannot trigger a ventricular pulse and hence
cannot trigger a PMT (see Figure 14).
Figure 14: VES starts the ARP to prevent pacemaker-mediated tachycardia
Atrial Refractory Period Extension
In the case of a programmed atrial refractory period extension, the
atrial refractory period is extended by the programmed value after a
ventricular event, if the event
• is a ventricular sensed event without a preceding atrial event (VES);
pacing modes: DDD(R), DDT(R), VDD(R), VDT(R),
• is a ventricular pace event that has not been triggered by a P wave;
pacing modes: VDD(R), VDT(R).
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73
Antitachycardia Functions
An atrial refractory period extension might be necessary in the case of
a short atrial refractory period in conjunction with a long VA
conduction period in order to prevent the triggering of a PMT by
asynchronous ventricular depolarizations.
PMT Protection
Pacemaker-mediated tachycardias can also be caused by artifacts and
atrial extrasystoles. In such cases, the PMT protection algorithm
provides functions for both reliable detection as well as termination of
PMTs. In this way the hemodynamically more favorable AV
synchronization can rapidly be reestablished.
PMT Detection
The period between a ventricular event and the sensing of a retrograde
P wave is designated as the VA delay or retrograde conduction: V p-As
interval (V p = ventricular pace, A s = a sensed atrial event). The VA delay
is a programmable parameter (VA criterion) and can be set between
250 and 500 ms.
A pacemaker-mediated tachycardia is recognized by the sensing
algorithm when the following criteria are satisfied:
• Eight consecutive V p-As intervals must be shorter than the
programmed VA delay.
• The average standard deviation of the eight Vp-As intervals must lie
within the tolerance limits of the PMT stability criterion.
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74
Antitachycardia Functions
If these two conditions are met, the pacemaker automatically extends
or shortens the AV delay by a defined value. If the resulting Vp-A s
interval remains constant, the PMT is considered confirmed. The
algorithm for terminating the PMT is automatically started.
Note:
In cases where a low upper tracking rate and long
AV delays have been programmed, pacing rates
slightly above the UTR may occur for a few cycles.
PMT Termination
The PMT is terminated by extending the total atrial refractory period
(TA RP) for a pacing cycle. This interrupts the retrograde conduction
loop and hence the PMT. Consequently, the PVARP must be longer
than the retrograde conduction period after ventricular pacing or
sensing. The duration of the PVARP depends on the duration of the
TA RP used in the systems and on the AV delay (PVARP = TARP minus
the AV delay).
Note:
A safety interval of 300 ms protects against
competitive pacing and prevents the atrial pulse
from reaching refractory and/or vulnerable tissue.
This safety interval cannot be programmed and is only active when the
PMT function is active.
Preventive Overdrive Pacing
Atrial overdrive pacing is a preventive measure to reduce the incidence
of atrial tachycardias. Numerous clinical studies and publications
indicate a decreased risk of developing atrial tachycardias. The
overdrive algorithm effects atrial overdrive pacing and ensures pacing
at a rate that is slightly above the intrinsic sinus rate. Atrial overdrive
pacing thereby minimizes the number of detected atrial events. The
overdrive mode is available in the modes DDD(R)+, DDT/A(R)+,
DDT/V(R)+, AAI(R)+ and AA T(R)+ .
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75
Antitachycardia Functions
Incremental Rate Increase and Decrease
Each time an atrial event is sensed, the pacing rate is increased by a
programmable increment (see Figure 15). This overdrive increment can
be set to either low (approx. 4 ppm), medium (approx. 8 ppm), or high
(approx. 12 ppm). If the intrinsic rate does not continue to rise after a
programmable number of cycles (the overdrive pacing plateau), the
overdrive pacing rate is reduced in increments of 1 ppm. The drop in
rate occurs each time after the programmed number of cycles has
been completed (see Figure 16). Values between 1 and 32 cycles can
be assigned to the overdrive pacing plateau.
Figure 15: Incremental rate increase in preventive overdrive pacing
The pacing rate is reduced until the next atrial event is sensed.
Subsequently, the overdrive cycle begins again with the rate increase.
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76
Antitachycardia Functions
Figure 16: Incremental rate reduction with preventive overdrive pacing
Safety Function of the Algorithm
Preventive overdrive pacing provides various safety functions which
are, for example, effective for high atrial rates:
• When the programmed maximum overdrive rate (MOR) is exceeded,
such as in the case of atrial tachycardias, then the algorithm is
automatically deactivated. Should the rate fall below the MOR, the
overdrive algorithm is reactivated.
• The function is likewise deactivated when the average atrial rate of
the last 64,000 cycles exceeds the average safety rate (ASR). In this
case, the pacing rate is incrementally decreased to the basic rate.
The ASR is dependent on the programmed basic rate and the MOR.
When the average atrial heart rate falls below the ASR, preventive
overdrive pacing is reactivated.
The overdrive remains permanently switched off after the fourth
deactivation due to the ASR being exceeded. The overdrive mode can
be reactivated only after the next interrogation of the pacemaker.
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77
Caution!
Antitachycardia Functions
When programming the DDD(R)+ overdrive mode,
you should check whether a pacemaker-mediated
tachycardia could be triggered on the basis of the
selected pacemaker program, and whether atrial
overdrive pacing might then develop.
If this is the case, we recommend programming
the maximum overdrive rate (MOR) for the atrial
overdrive to a value which is lower than the
expected rate of the pacemaker-mediated
tachycardia.
VES Lock-in Protection
Purpose
Terminating VES lock-in behavior by an atrial stimulus after detecting a
P wave during the refractory period. This function is particularly
suitable for patients with first-degree AV block.
Description
When ventricular extrasystoles (VES) occur, the following implant
behavior can occur:
—
When VES occur, the basic interval and atrial refractory period
are restarted. This enables the P waves to fall within the atrial
refractory period.
—
As a result, no ventricular pacing pulses are triggered by the P
waves. This implant behavior is termed VES lock-in.
—
To terminate this VES behavior, an atrial stimulus is emitted
during the refractory period after the atrial sense event to
resynchronize the implant with the cardiac activity.
The VES lock-in protection function can be optionally activated, and
you have the option to set the number of detection cycles.

78
Rate Adaptation
Rate Adaptation
Cylos uses two completely separate principles for rate adaptation:
• Rate adaptation by an accelerometer
• Physiologic rate adaptation using Closed Loop Stimulation
The programmable rate-adaptive modes fall into the following
categories:
Rate Adaptation
Closed Loop
Stimulation
Accelerometer-based
physiological
rate adaptation
activity modes
atrial overdrive
pacing
DDD-CLS
VVI-CLS
DDDR
DDIR
DDITR
DDTR
DDTRA
DDTRV
DVIR
DVTR
VDDR
VDTR
VDIR
VVIR
VVTR
V00R
AAIR
AATR
A00R
D00R
DDDR+
DDTR+
DDTRA+
DDTRV+
AAIR+
AATR+
Table 7: Overview of rate adaptation
Accelerometer-Based Rate Adaptation
Sensor-controlled rate adaptation allows an adjustment of the pacing
rate to changing metabolic needs at rest and during exertion. The
pacing rate increases at the onset of exercise to the sensor-determined
rate. It slowly returns to the basic rate when exercise is no longer
detected.

79
Rate Adaptation
The pacemakers are equipped with an accelerometer that is integrated
into the hybrid circuit. This sensor produces an electric signal that is
constantly processed by analog and digital signal facilities. If a rateadaptive mode is programmed, then this effects an adjusted increase
of the basic rate, depending on the exertion level of the patient. With
the sensor being integrated in the hybrid circuit, it is not sensitive to
static pressure on the pacemaker housing.
The sensing and inhibition function remains activated during sensorcontrolled operation. In case of high pacing rates, however, the
refractory periods may cover a majority of the basic interval, resulting
in asynchronous operation.
Convenient diagnostics features allow you to quickly set individual and
optimal rate adaptation for the patient (see the section on “Follow-up
Options” for more details).
Physiologic Rate Adaptation (The CLS Feature)
How Closed Loop Stimulation Works
The contraction dynamics of the myocardium vary depending on the
patient's exertion. These changes are characteristic, allowing Closed
Loop Stimulation to determine a pacing rate that is patient-specific
and physiologically appropriate. This also applies to times when the
patient is emotionally stressed.

80
Rate Adaptation
The pacemaker evaluates the dynamics of the myocardial contraction
quickly after ventricular contraction. Impedance is measured via a
ventricular lead and is largely dependent on the specific conductivity of
a small volume of tissue surrounding the electrode tip.
Changes in impedance are characteristic of ventricular contraction and
are directly proportional to heart stress. The pacemaker calculates the
necessary pacing rate by measuring the current impedance and
comparing it with impedance data that was measured at rest. CLS is
able to immediately respond to exertion by using contractility as input
for rate adaptation. There is therefore no need to combine CLS with
accelerometer-based rate adaptation.
Closed Loop Stimulation is self-calibrating and automatically adjusts to
the patient's situation within just a few minutes. Typically, there is no
need to manually fine-tune the system. Automatic fine-tuning
continually occurs throughout the entire service time of the
pacemaker.1
It may be necessary to adjust the CLS in individual cases, as when a
patient is extremely active or inactive.
Among other things, the baseline impedance curves used for comparison are regularly
updated by pacing cycles with extended or reduced AV delays.
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81
Rate Adaptation
Individually Adjusting CLS Parameters
The following parameters can be individually adjusted with the
“extended CLS settings”:
• The required V P
• The CLS dynamics
• Dynamic runaway protection
The Required V P
In the DDD CLS mode, the default setting includes AV hysteresis to
support existing adequate intrinsic conduction. For patients with
inadequate or non-existing intrinsic conduction, it may be necessary to
turn off AV hysteresis. To do this, turn on the parameter [required V P].
CLS Dynamics
The factory settings for Closed Loop Stimulation provide most patients
with optimum rate dynamics. Typically, there is no need to make
adjustments.
The rate profile resulting from Closed Loop Stimulation can vary
greatly from patient to patient. In individual cases, the rate dynamics
can be optimized if the rate distribution is inadequate.
The [CLS Dynamics] parameter influences the pacemaker-internal
target rate, which is dependent on two other pre-set parameters: the
basic rate and the maximum closed loop rate. The pacemaker
internally controls rate adaptation so that 20% of the pace events are
always above the internal target rate. If CLS dynamics are
reprogrammed to a higher value, then the rate distribution includes
higher rates, and vice versa: lower programmed values yield rate
distribution with lower rates.
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82
Rate Adaptation
Dynamic Runaway Protection
This parameter sets the pacing rate attainable during rest to a
programmable value,1 for example 20 ppm, above the preset basic
rate. This suppresses any non-specific rate fluctuations at rest without
limiting the rate adaptation under mental stress. In cases where
runaway protection is not clinically appropriate, this feature can be
turned off.
The CLS Safety Feature
The pacemaker regularly checks internally that everything needed for
correct Closed Loop Stimulation is available. If one of these
requirements is not met, then Closed Loop Stimulation is interrupted,
and the pacing rate is lowered to the sensor rate. As soon as all
requirements are met, Closed Loop Stimulation automatically restarts.
The following events interrupt Closed Loop Stimulation:
• Automatic initialization of CLS
• Mode switching
• Ventricular fusion beats
• Inadequate impedance values
• Hardware and software errors
Automatic Initialization of Closed Loop Stimulation
CLS Standby Mode
Closed Loop Stimulation has been pre-installed and deactivated in the
implant, meaning CLS is in standby. Following auto-initialization, the
user is prompted to activate Closed Loop Stimulation or not (see the
section on “Auto-initialization” for more information).
The exact value depends on the ratio of the basic rate to the maximum Closed
Loop rate, see the “Technical Data” section on page 147.
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83
Rate Adaptation
Sensor Gain
The sensor gain designates the factor by which the electric signal of
the sensor is amplified before subsequent signal processing occurs.
The programmable sensor gain permits adaptation of the desired rate
adaptation to the individually variable signal strengths. The optimum
setting is achieved when the desired maximum pacing rate is attained
during exertion (see Figure 17).
Before adjusting the sensor gain, the rate increase, rate decrease, and
maximum sensor rate parameters must be checked for their suitability
with respect to the individual patient.
If the rate increase is not sufficient during high levels of physical
exertion, the sensor gain should be increased. On the other hand, the
sensor gain should be reduced if high rates are obtained at low levels
of exertion.
Note:

Apart from the manual adjustment of the sensor
gain, an automatic sensor gain function is available
(see the "Automatic Sensor Gain" section).
84
Rate Adaptation
Figure 17: Impact of sensor gain on rate adaptation
Automatic Sensor Gain
The manually programmable sensor gain is supplemented by an
automatic sensor gain function. When the function is enabled, the
pacemaker continuously checks whether sensor gain optimally
corresponds to the patient's needs and makes adjustments as
necessary.
The "automatic sensor gain" function checks daily whether 90% of the
set "maximum sensor rate" (MSR) has been reached for a total of 90
seconds. When this occurs, it reduces the sensor gain by one
increment.
If the "maximum activity rate" is not achieved, the current setting will
initially remain unchanged. If the MSR is not reached within a period of
seven days, sensor gain will be increased by one step (see Figure 17).
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85
Rate Adaptation
Figure 18: Automatic adjustment of sensor gain with a 7:1 algorithm
Sensor Threshold
The minimum strength of the signals used for rate adaptation is
determined with the programmable sensor threshold. Sensor signals
below this threshold do not affect rate adaptation (see Figure 19).
Through the programmable sensor threshold, a stable rate at rest of
the patient can be achieved by ignoring low-amplitude signals that
have no relevance for increased levels of physical exertion.
If the pacing rate at rest is unstable or reaches values that are above
the basic rate, the sensor threshold should be increased. On the other
hand, the sensor threshold should be reduced if a sufficient rate
increase is not observed with slight exertion. The sensor gain should be
adjusted before setting the sensor threshold.
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86
Rate Adaptation
Figure 19: Only signals above the programmed threshold influence the rate
adaptation
Rate Increase
The rate increase parameter determines the maximum speed by which
the pacing rate rises if the sensor signal indicates increasing exertion
(see Figure 20).
When the rate of increase is set to 2 ppm per cycle, the rate increases
from 60 ppm to 150 ppm in 45 cycles, for example.
The programmed rate increase applies only to sensor-controlled
operation and does not affect the rate changes during atrial-controlled
ventricular pacing.
Figure 20: Rate increase during exertion
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87
Rate Adaptation
Maximum Activity Rate
Regardless of the sensed amplitude of the sensor signal, the pacing
rate will not exceed the programmed maximum activity rate (see Figure
21).
The programmed value applies only to the maximum pacing rate
during sensor-controlled operation and is independent of the upper
tracking rate.
Figure 21: Maximum activity rate
Note:
In the DDIR and DVIR modes, lower maximum
sensor rates result than those indicated here,
depending on the selected AV delay. The correct
values are indicated by the programmer.
The shorter the selected AV delay is, the higher the
maximum sensor rates can become.
Rate Decrease
The value programmed for the rate decrease determines the maximum
speed by which the pacing rate is reduced when there is a fading
sensor signal (see Figure 22).
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88
Rate Adaptation
Setting the decrease speed to 0.5 ppm per cycle means that the rate
decreases from 150 ppm to 60 ppm in 180 cycles, for example.
In the modes DDIR and DVIR, the rate decrease is slightly slower than
indicated here (partly depending on the programmed AV delay).
The programmed rate decrease setting applies only to the decrease in
pacing rate during sensor-driven operation and does not affect the
pacing rate during atrial-controlled ventricular pacing.
Figure 22: Rate decrease following exertion
Sensor Simulation
Even when a non-rate-adaptive mode is programmed, the sensor
response is recorded without it even having been activated. In other
words, the sensor simulation indicates how the sensor would have
responded if a rate-adaptive mode had been programmed.
This function is helpful to find the optimum sensor settings and to
compare the sensor rate with the intrinsic rate.

89
Rate Adaptation
Thus, sensor information is available prior to the activation of the rate
adaptation, which can be used to evaluate the sensor response (see
also the "Sensor Histogram" and "Activity Chart" sections under
"Diagnostic Memory Functions").
Note:
In the sensor simulation, you can only select
sensor threshold values that are greater than those
used in the permanent program.
Rate Fading – Rate Smoothing
In all atrial-controlled modes, controlled rate fading during a sudden
incident of bradycardia leads to a more favorable adjustment of the
pacemaker’s pacing rate to the patient’s intrinsic rate.
When controlled rate fading is enabled, the pacemaker calculates a
"backup rate" that is always active in the background. As soon as the
rate decreases, the pacemaker paces at the backup rate. The backup
rate follows with a certain delay of the intrinsic rate corresponding to
the programmable rate increase (1; 2; 4; 8 ppm/cycle) and the
programmable rate decrease (0.1; 0.2; 0.5; 1.0 ppm/cycle). These
settings determine the sensitivity of the rate fading.
Figure 23: Rate fading after a physiological rate increase

90
Rate Adaptation
After four consecutive A S, the target rate for the backup rate is
calculated from the current atrial sensing rate minus 10 ppm. AES and
AP set the target rate to the value of the basic/sensor rate.
Figure 24: Controlled rate fading after a sudden incident of tachycardia
If atrial tachycardia occur suddenly triggering a mode switch, the
target rate is set to either the sensor or basic rate. The current pacing
rate in the ventricle is determined from the current value of the backup
rate prior to the mode switching event.
If the pacing rate reaches the intrinsic rate during the rate drop, at
least four consecutive intrinsic cycles above the pacing rate are
required before the pacing rate is once again adapted to the last
intrinsic event.
Controlled rate smoothing is thereby continued during intermittent
sense events.

91
Rate Adaptation
Figure 25: Updating the backup rate (rate fading), P=pacing, S=sinus rhythm
Four consecutive intrinsic sense events are necessary to activate rate
fading. Individual sense events do not affect rate fading.
Backup Rate
Rate that the pacemaker uses to pace when there is a
sudden rate decrease. This can be a maximum of 10
ppm less than the intrinsic rate and follows the target
rate with an increase of 1,2,4, or 8 ppm per cycle, or
0.1...1 ppm per cycle if the target rate is less than the
current backup rate.
Target Rate
The target rate is either the current detection rate
minus 10 ppm, or the sensor/basic rate. The backup
rate follows the target rate with the programmed rate
increase or decrease.
Table 8: Backup rate and target rate
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92
IEGM Recordings
IEGM Recordings
Purpose
This function makes it possible to automatically record the progression
of intracardiac events. These recordings are made between follow-ups
and provide diagnostic information about the origin of the tachycardia,
especially the time just prior to a tachycardia episode.
Description
When the preset criteria are satisfied, the IEGM recordings are
automatically started and data are recorded for up to 10 seconds. The
recordings can be shorter if the rates and amplitudes are high.
A maximum of 20 IEGM recordings is possible, and each recording
type can be assigned a specific number according to the memory
management priorities.
Optimized Memory Management
The IEGM recordings are saved in the order that they occur until all
memories are full. With this principle, these IEGM recordings are not
overwritten, and thus not deleted:
• The last 3 patient IEGMs that were activated by magnet application
• 4 IEGMs for the atrial rate or mode switching:
— The oldest, longest, most recent recording for the atrial rate and
highest ventricular value recorded
• 3 IEGMs for high ventricular rates:
— The longest, highest, and most recent recording

93
IEGM Recordings
When all 20 IEGM memories are full, the device searches for disk
space that is not protected and will record the following:
• The oldest recording for the ventricular rate
• The oldest recording, triggered by magnet application
• The oldest recordings for mode switching, a high atrial rate and
PMT termination
When the maximum number of entries is exceeded, then the oldest
recordings are overwritten (meaning there is a loop memory principle
in place for each recording type). The first recording and the
recordings with the longest duration for each event type are archived
and are available for viewing.
During the follow-up treatment, IEGM recordings can be interrogated
and displayed.
Types of IEGM Recordings
Overview
The different types of IEGM recordings are initiated by the following
events, and you can program their criteria:
IEGM recording at a high atrial rate (HAR)
IEGM recording during mode switching (MSW)
IEGM recording during high ventricular rate (HVR)
IEGM recording during PMT termination (PMT)
IEGM recording by patient (PA T)
Cylos VR
In VVI(R) mode, only the HVR type of IEGM recording is available. In
AAI(R) mode, only the HAR type of IEGM recording is available.
IEGM Recording during High Ventricular Rates
This type is initiated by high atrial rates and atrial tachycardias.
Recordings at high atrial rates are determined by the following
parameters:
—
The atrial detection rate defines how high a rate must be before
atrial tachycardia is considered definite and the recording is
started.

94
IEGM Recordings
IEGM Recording during Mode Switching
This type is initiated by mode switching. The parameters can only be
set in the Mode Switching function.
Note:
Do not activate IEGM recording for high atrial rates
and for mode switching at the same time.
IEGM Recording during High Ventricular Rates
This type is initiated by high ventricular rates and ventricular
tachycardias. The following parameter triggers recording during high
ventricular rates:
—
The ventricular detection rate determines how high a rate must
be before ventricular tachycardia is considered definite and the
recording is started.
IEGM Recording Triggered by the Patient
The patient can start the recording by placing a magnet (M50) over the
implant.
Note:
Program the magnet effect to [synchronous] when
IEGM recording should be possible by the patient.
Caution!
Due to the compression and reconstruction
processes that the signals undergo, the IEGM
recordings are not suitable for direct morphologic
analyses. If you have activated the "patienttriggered IEGM recording" function, please tell the
patient how to use the magnet to trigger an IEGM
recording.
Have the patient review the information included
with the pacemaker, including the section entitled
"Storing Intracardiac Data Through Magnet
Application."

95
IEGM Recordings
IEGM Recording during PMT Termination (PMT)
This type starts a recording at the end of a PMT. The PMT protection
function must be activated beforehand, however.
Displaying IEGM Recordings
After the list of IEGM recordings has been selected, the desired IEGM
recording is selected and interrogated. The data are read from the
implant and displayed in the associated window as a graph.

96
Diagnostic Memory Functions (Statistics)
Diagnostic Memory Functions (Statistics)
Overview
The diagnostic memory functions are divided into the following five
groups of statistics that in turn contain various subgroups. These are
the following:
• Timing statistics
—
Timing events
—
Special events
—
Atrial rate histogram
—
Ventricular rate histogram
—
A/V rate trend
—
Far-field histogram
—
Histogram showing intrinsic AV conduction
• Arrhythmia statistics
—
Tachy episode trend
—
AT histogram
—
AES trend
—
AES versus atrial rate
—
AES coupling interval
—
VES classification
—
VES versus ventricular rate
—
VES coupling interval
• Sensor statistics
—
Rate / sensor trend
—
Sensor gain trend
—
Sensor histogram
—
Activity chart
• Sensing statistics
—
P-wave trend (short- and long-term trend)
—
R-wave trend (short- and long-term trend)
• Pacing statistics
—
A/V impedance trend (short- and long-term trend)
—
Ventricular (pacing) amplitude trend
—
Ventricular threshold trend
—
Ventricular (pacing) amplitude histogram
—
ACC status

97
Diagnostic Memory Functions (Statistics)
Description of
Displays
The contents of the diagnostic memory are displayed as a combined
text/graphical image, with the following display options:
—
Event counters
—
Histograms
—
Trends
Event counters are displayed as bar charts showing the event totals
expressed as a percentage.
Histograms count the frequency of events in different time or rate
intervals (e. g., how many events have occurred in the 160-169 ppm
range).
Trends represent a certain number of events at a fixed point in time
(e.g., rates). The trends are plotted as points that are joined together
by a curve. For instance, if two curves are displayed in a diagram for
dual-chamber pacemakers, the thicker line always represents the
ventricular trend, and the thinner line is always the atrial trend.
Note:
Applying a magnet interrupts diagnostic data
recording, regardless of the programmed magnet
effect.
Interrogating and/or Starting Statistics
The recorded diagnostic data (the saved data contents of the
pacemaker) are always read out (meaning they are transmitted during
interrogation) at the beginning of a follow-up treatment, and saved in
the programmer. This allows you to call up the relevant data via the
programmer at any time. After which, when recording of the same
statistical data is started up once again, any pre-existing statistics are
deleted from the pacemaker memory. Therefore, the user is prompted
for confirmation before a new statistics function can be started. This
safeguard prevents you from inadvertently overwriting statistics data if
you are starting the same statistics function again and again. For more
detailed information on saving statistics data and the transmission of
pacemaker data to the Cardiac Data Manager 3000, please consult the
technical manual of the software.

98
Diagnostic Memory Functions (Statistics)
Timing Statistics
Timing Events
The display of the event counter varies depending on the kind of
pacing. In addition to the graphic display, absolute values of the event
counter are displayed. The event counters are categorized into three
groups:
—
All transitions
—
Atrial sensing (A sense) and atrial pacing (A pace)
—
V sense and V pace
The event counter can register the following events and event
sequences over a time period of several decades:
—
Atrial sensing A S (outside the ARP)
Atrial pacing A P
—
—
Ventricular sensing VS (outside the VRP)
Ventricular pacing VP
—
—
Event sequences:
A S followed by V S
—
A S followed by VP
—
AP followed by VS
—
AP followed by VP
—
—
V followed by V1 (ventricular extrasystole = VES)
—
A RS refractory sense events in the atrium
—
V RS refractory sense events in the ventricle
The event sequence V—V means two consecutive ventricular events
(sensing or pacing) without a previous atrial event.
In this context, V - V means that all possible ventricular events can follow, such as
VS, VP and/or VES.

99
Diagnostic Memory Functions (Statistics)
Ventricular extrasystoles are counted both as VES as well as ventricular
sense events.
Special Events
The following events can be recorded:
—
Successful AV scan hysteresis
—
Overdrive safety switch-off
—
Mode switching counter
—
PMT termination
—
VES lock-in protection
Note:
All event counter data are transmitted to the
programmer and evaluated there, but not all events
are displayed in detail on the programmer.
Atrial and Ventricular Rate Histogram
Dual-chamber pacemakers are equipped with a separate atrial and
ventricular histogram. A bar chart displays the heart rate percentages
as well as the absolute values. The number of times a heart rate occurs
within certain rate ranges is recorded separately according to sensing
and pacing. The rate range is divided into 16 equidistant rate classes
between 40 and 180 ppm. The distribution of occurring heart rates
can be displayed in a chart during follow-up.
Valid for Cylos DR and
Cylos DR-T
A/V Rate Trend
The A/V rate trend is displayed as a line chart and consists of the heart
rate trend and the pacing rate trend. Both atrial as well as ventricular
events are recorded at a fixed point in time. There are two available
kinds of recording, a short-term trend ([12 min/fixed]) and a long-term
trend ([auto/rolling]). The long-term trend begins with a resolution of 2
seconds with 120 time intervals, the time intervals are continually
compressed and in the last compression level the recording takes
place with a resolution of 512 seconds and 180 time intervals.
Subsequently, the long-term trend is recorded in repetitive cycles. The
general rule is that the shorter the recording interval, the higher the
resolution. The short-term trend thus serves to create a very exact
recording of short-term rate changes, for instance during an exercise
test.

100
Diagnostic Memory Functions (Statistics)
In the A/V rate trend, the heart rate in ppm is recorded in the upper
chart, and the percentage distribution of the pacing rate is recorded in
the lower chart. The ventricular curve for the heart rate as well as for
the pacing rate is indicated by a thicker line than the atrial curve.
Far-Field Histogram
The frequency of events that fall within the far-field interval is recorded.
The rate range between < 50 and > 190 ppm is divided into 16
equidistant rate classes. The graphical display shows the percentages
of the individual classes in the form of a bar chart and the total
number of events.
The far-field histogram can only be selected for the following pacing
types:
—
DDD(R), DDI(R), VDD(R), DDIT(R), VDT(R), VDI(R), DDT(R),
DDT/A(R), DDT/V(R)
—
DDD(R)+ , DDT/A(R)+, DDT/V(R)+
Valid for
Cylos DR
Intrinsic AV Conduction
Statistics from intrinsic AV conduction help optimize the programmed
AV delay and AV hysteresis. Within a single rate class, the cases of
intrinsic conduction are displayed in relationship to the programmed
AV delays and AV hystereses as a histogram for atrial pace and sense
events. On the left side of a rate class (< 70; 70-90; 90-110; 110-130;
> 130 bpm), instances of intrinsic conduction following atrial pace
events are shown. On the right, we see instances of intrinsic conduction
following atrial sense events. Totals for A SV S and A PVS within a specific
rate class are shown on the printout, as are overall totals.

101
Diagnostic Memory Functions (Statistics)
Arrhythmia Statistics
The pacemaker monitors the cardiac rhythm and characterizes it
according to the following classification criteria:
—
SR (sinus rhythm)
—
ST-A T range (sinus tachycardia/atrial tachycardia)
—
Afl/AF range (atrial flutter/atrial fibrillation)
Arrhythmia detection does not occur at any individual interval, but
rather within arrhythmia ranges with suitable criteria. These criteria
are described below.
Mode Switching
The tachy event trend can only be selected for the following modes:
—
DDD(R) and DDD(R)+
—
VDD(R)
—
DDT(R)/A and DDT/A(R)+
—
DDT(R)/V and DDT/V(R)+
If this is not taken into account, a corresponding error message
appears on the screen of the programming device. The tachy event
trend can only be selected when mode switching has been set. The
tachy event trend registers atrial tachycardias (PA T) that are
recognized by the pacemaker and lead to mode switching. The last
atrial tachycardias (up to 64) are recorded. Several consecutive mode
switching events within 45 sec triggers recording of a tachy event.
The tachy event trend displays the atrial tachycardia events graphically
as a function of time. The respective date and time at the beginning
and end of the tachycardia events are also printed out. This documents
both the frequency and length of the tachycardia periods, which can be
evaluated at follow-up.

102
Diagnostic Memory Functions (Statistics)
The tachy event trend is automatically started by activating the mode
switching function. The memory contents are deleted and the memory
function is restarted with every permanent programming and every
restart of the mode switching function. It is not possible to manually
switch off the tachy event trends while the mode switching function is
activated.
The beginning and end times of the tachycardias are saved with a
resolution of 2 seconds. The counter evaluates tachy episodes within
the entire follow-up time period.
Note:
When the elective replacement indication (ERI) has
been attained, the content of the tachy event
trends as well as all other memory contents are
"frozen," and recording is stopped.
When Are Atrial Sense Events Classified as AES?
AES Classification
The basis for evaluating whether an atrial extrasystole (AES) has
occurred is provided by the atrial extrasystole value window (AESW).
The objective of the absolute atrial refractory period (AARP) is to
simulate the natural refractory period in the atrium. Atrial events
occurring during AARP are not classified as AES. The AARP is
shortened dynamically as the rate increases. The AESW is limited by
an AARP and an atrial prematurity.
The window of time for an AES cannot exceed a maximum interval
length of 800 ms. An atrial sense event that is detected 800 ms or
more after the last atrial event is no longer classified as an AES.

103
Diagnostic Memory Functions (Statistics)
Figure 26: AES/AT classification
Atrial sense events that occur within the AESW are classified as AES.
The AESW timing is triggered under the following conditions:
—
—
—
The AESW starts at the end of the AARP until the requirement for
atrial prematurity is met.
The requirement for atrial prematurity can be programmed
within the range of 5...(5)...50%.
The atrial prematurity is the percentage of the last four PP
intervals.
An atrial prematurity of 25% means that an atrial sensed event
qualifies as an AES when the PP interval is at least 25% shorter than
the average of the last 4 PP intervals.
Determining Arrhythmia Ranges
The diagnostically relevant arrhythmia ranges are limited by rate
limits.

104
Diagnostic Memory Functions (Statistics)
Figure 27: Arrhythmia detection
The diagnostically relevant arrhythmia ranges can be set as follows:
—
ST/A T range between 80...(10)...200 ppm
—
Afl/AF range between 100...(10)...400 ppm
In addition to the arrhythmia ranges, other criteria must be fulfilled:
—
Activation criteria
—
Atrial rate stability
—
Sudden rate increase
Note:
All classifications are exclusively for diagnostic
purposes, i.e., in case of arrhythmia this fact is
documented, but the cardiac pacemaker does not
automatically respond with therapy.
AT Histogram
In the A T histogram, the events are displayed in 9 arrhythmia ranges,
whereby the number and type of the ATs are indicated. The transitions
from a tachycardic phase to other phases as well as the number of
episodes are counted.
The programmed areas of the various ATs are also displayed.

105
Diagnostic Memory Functions (Statistics)
AES Trend
In the AES trend, the sequence of atrial extrasystoles per minute is
displayed in the form of a line chart. The AES trend is a rolling longterm trend with a recording time of 180 days and a resolution of 24
hours. 0-100 AES/min. are displayed.
In addition, individual AES, couplets, triplets, the shortest Ax-AES
interval, and the maximum number of AES per hour are displayed.
AES Versus Atrial Rate
The display of the AES vs. atrial rate histogram takes place in 16
equidistant rate classes of < 31 to > 179 ppm. The graphical display
shows the percentages of the individual classes in the form of a bar
chart and the total number of events.
AES Coupling Interval
The AES coupling interval shows in which millisecond range the
prematurity has taken place. The intervals of the AES—AES sequences
are displayed from 126 to > 1499 ms in 16 histogram classes. The
graphical display shows the percentages of the individual classes in the
form of a bar chart and the total number of events.
VES classification
This function permits long-term recording (over several years) and
classification of ventricular extrasystoles (VES). Events that occur in
one of the two following situations are classified as VES:
• When a ventricular event without a preceding sensed or paced event
takes place,
— then the Vx-Vs interval must be shorter than 500 ms in order
for the ventricular (Vs) event is classified as VES.
• When a preceding atrial event is sensed during the refractory
period,
— then the Ars-Vs interval must be longer than 300 ms in order
for the ventricular sense event to be classified as VES.

106
Diagnostic Memory Functions (Statistics)
Hence it is recommended that you ensure that stable atrial sensing
exists prior to the activation of the VES analysis. If the atrial lead is
bipolar, bipolar sensing should be considered.
The event counters of the VES classification are subdivided into three
percentage classes:
—
0 - 25%
—
25 - 50%
—
 50%
In addition, individual VES, couplets, triplets, runs, tachycardias and
the maximum number of VES per hour are displayed.
VES Versus Ventricular Rate
The VES vs. ventricular rate is likewise displayed in a histogram with
16 equidistant classes of < 40 to >179 ppm. The graphical display
shows the percentages of the individual classes in the form of a bar
chart and the total number of events.
VES Coupling Interval
The VES coupling interval documents the time difference between a
regular ventricular event and subsequent VES of 0 to 500 ms duration.
This display corresponds to the three event counters of prematurity at
0-25%, 25-50% and > 50%. The graphical display shows the
percentage value of the individual classes in the form of a bar chart
and the total number of events.

107
Diagnostic Memory Functions (Statistics)
Sensor Statistics
The sensor statistics contain the recording of the rate trend and sensor
trend. A setting of [12 min/fixed] integrates the sensor optimization.
Rate / Sensor Trend
The rate / sensor trend is displayed in the form of a line graph
containing the length of the time intervals and the trend data. The
permanent sensor parameters can be edited at the setting [12
min/fixed]. The edited sensor parameters are simulated and displayed
as a trend.
The thicker line corresponds to the recorded trend, and the thinner line
to the simulated trend.
Sensor Gain Trend
The sensor gain can be recorded up to 180 days (rolling). The sensor
gain is displayed on a semi-logarithmic scale from 1 to 40 with a time
resolution of 2 s to 24 h, depending on the recording duration.
Sensor Histogram
The frequency with which the sensor rate occurs in certain rate ranges
is recorded. The rate range is divided between < 40 to > 179 ppm into
16 equidistant rate classes. The graphical display shows the
percentages of the individual classes in the form of a bar chart and the
total number of events.
The recording of the sensor rate does not depend on whether the
respective pacing rate was active or whether pacing did not occur due
to intrinsic events.

108
Diagnostic Memory Functions (Statistics)
Activity Chart
The activity chart on the programmer is divided into three ranges:
"MAR" (maximum activity rate), "Activity", and "No Activity." The activity
range indicates the time in which the sensor was active, but not with
the maximum sensor rate. All values are expressed as percentages.
Sensing Statistics
P-Wave Trend
This is where the course of sensitivity in the atrium is displayed. The Pwave trend is displayed in the form of a line chart. The P-wave trend is
a rolling trend and records values in the range of 0.0 to 7.5 mV. The Pwave trend can be:
—
A long-term trend with a recording duration of 180 days
—
A short-term trend with a recording duration of 33 hours
The long-term trend can be displayed only after recording has been
running for 3 days.
R-Wave Trend
This is where the sensitivity course in the ventricle is displayed. The Rwave trend is displayed in the form of a line chart. The R-wave trend is
a rolling trend and records values in the range of 0.0 to 15 mV.
The R-wave trend can be:
—
A long-term trend with a recording duration of 180 days
—
A short-term trend with a recording duration of 33 hours
The long-term trend can be displayed only after recording has been
running for 3 days.

109
Diagnostic Memory Functions (Statistics)
Pacing Statistics
Ventricular (Pacing) Amplitude Trend
The ventricular (pacing) amplitude trend is a long-term trend that
records values in the range of 0.0 to 10 V with a recording duration of
180 days.
Ventricular Threshold Trend
The ventricular threshold trend is a long-term trend that records values
in the range of 0.0 to 8 V with a recording duration of 180 days.
Ventricular (Pacing) Amplitude Histogram
The frequency with which ventricular pacing occurs in certain ranges –
in the context of the amplitude control (ACC) function – is recorded.
The range between < 0.3 V and > 4.8 V is divided into 16 equidistant
classes. The graphical display shows the percentages of the individual
classes in the form of a bar chart and the total number of events.
ACC Status
The ACC statistics shows the following for the active capture control
(ACC) function:
—
The last measured threshold
—
Status of the active capture control function
—
Indication of the "deactivated" and “high pacing threshold” status
A/V Impedance Trend
In the pacemaker, the atrial and ventricular impedances are measured
every 1.5 hours, and both values are displayed in the A/V impedance
trend in the form of a line chart. The AV impedance trend is a rolling
trend. The values of the A/V impedance trend lie between 0 and 3000
Ohm. The AV impedance trend is possible as the following:

110
—
—
Diagnostic Memory Functions (Statistics)
Long-term trend with a recording time of 180 days and a
resolution of 24 hours
Short-term trend with a recording time of 33 hours and a
resolution of 1.5 hours
The thicker line represents the ventricular impedance curve, the
thinner line the atrial impedance curve.

111
Follow-up Options
Follow-up Options
The pacemaker is equipped with an extensive array of automatic
functions that greatly simplify the adjustment and monitoring of the
pacing system and reduce the time required for follow-up
examinations. These functions include, for instance, automatic
interrogation of all programmed and memory data at the beginning of
the follow-up examination; the status window displays pacemaker
response at BOS (beginning of service) and ERI (elective replacement
indication, see the section on replacement indications for more details)
with and without a magnet applied, the date of the last follow-up
examination, and other information about the condition of the
pacemaker.
Note:
Programming and additional information about the
individual functions are described in the technical
manual of the corresponding software module.
Realtime IEGM Transmission with Markers
The pacemaker offers the option of realtime transmission of the filtered
or unfiltered intracardiac electrogram (IEGM) to the programmer. The
filtered signal is used for the pacemaker timing. The programmable
settings relate to the filtered signal. Therefore only the filtered IEGM is
suitable for selecting a proper sensitivity setting. A simpler alternative
is to use the P/R-wave test to determine the amplitudes of the
intracardiac signal. In dual-chamber systems it is possible to transmit
and display the atrial and ventricular IEGM simultaneously. During
dual-chamber operation, the IEGM can be derived from the atrium and
ventricle simultaneously with a sampling rate of 5 to 60 Hz. If the IEGM
is derived either from the atrium or the ventricle, a sampling rate of 5
to 80 Hz is used.

112
Follow-up Options
The IEGM is transmitted together with the atrial and ventricular
markers for sensing, pacing, and sensing within the refractory period.
The IEGM, markers, and surface ECG can be displayed directly on the
programmer screen, printed by the programmer printer, or output to
an external ECG recorder.
IEGM Recordings
Purpose
The recording of intracardiac information over a short period of time
before a tachycardia phase provides valuable details about the
arrhythmogenesis of tachycardia. An IEGM recording can be triggered
by the following events:
• IEGM recording during high ventricular rates
• IEGM recording during mode switching
• IEGM recording during high ventricular rates
• IEGM recording during PMT termination
• IEGM recording triggered by the patient
Description
Every instantaneous recording provides information from the recording
period about the following:
• Type of triggering event
• The time and date of the recording
• Sensed and paced events in the atrium and ventricle including
refractory events
• Duration and filtered amplitude of the sensed events
• Number of measured maximum values within every sensed event
The recordings are stored according to a specific system. The aim is to
take optimal advantage of memory storage space as well as to record a
uniform number of images of every type of event if possible, while
simultaneously taking into consideration the above-mentioned priority
ranking of triggering events. During the next follow-up, the programmer
will automatically indicate that instantaneous recordings of arrhythmia
have been recorded. An appropriate command displays the recording
on the screen.

113
Follow-up Options
Note:
Program the magnet effect to [synchronous] when
you want the patient to do IEGM recording.
Caution!
Due to the compression and reconstruction
processes that the signals undergo, the IEGM
recordings are not suitable for direct morphologic
analyses. If you have activated the "patienttriggered IEGM recording" function, please tell the
patient how to use the magnet to trigger an IEGM
recording.
Have the patient review the information included
with the pacemaker, including the section entitled
"Storing Intracardiac Data Through Magnet
Application."
Analog Telemetry of Battery, Pulse and Lead Data
The following pulse, battery, and lead data can be measured noninvasively by means of analog telemetry:
Parameters
Unit of Measurement
Battery Voltage
Battery Impedance
kz
Battery Current
µA
Pulse Voltage
Pulse Current
mA
Pulse Energy
µJ
Pulse Charge
µC
Lead Impedance
Table 9: Measurable parameters of analog telemetry

114
Follow-up Options
Rate and Sensor Trend
The rate trend is a real-time trend, whereas the sensor trend is a
simulated trend.
Sensor Trend with Rate Forecasting
Valid for Cylos
The pacemaker can record the sensor rate curve over a period of 12
minutes to optimize sensor rate settings. The resolution is four
seconds. Recording stops automatically after 12 minutes.
After the sensor trend has been recorded, the rate forecast function
can simulate various settings for every parameter that influences the
rate (for example sensor gain, sensor threshold, maximum activity
rate, basic rate, etc.).
This makes it easier to optimize rate-adaptive parameters, since
repeated exercise tests are no longer necessary.
Note:
With sensor simulation you can only select values
of the sensor threshold that are greater than those
used in the permanent program.
High-Resolution Threshold Test
For facilitating follow-up, the pacemaker features a high-definition
threshold test with a resolution of 0.1 V in the range of 0.1 to 4.8 V.
The test is activated as a temporary program. Lifting the programming
head or pressing the key terminates the threshold test and makes the
pacemaker immediately revert to the permanent program.
During the threshold test, the pacing rate should be higher than the
spontaneous rate to avoid competitive pacing.

115
Follow-up Options
Automatic Threshold Test in the Ventricle
The prerequisites for an automatic threshold test in the ventricle are as
follows:
• Ventricular rate

100 bpm
• Adequate signal quality
• The implant is not set to mode switching
P/R-Wave Test
A P/R-wave test is available for measuring the amplitude of
spontaneous events during follow-up examinations. This test measures
the minimum, mean, and maximum amplitude values over several
cycles. This provides a simple and reliable method for adjusting the
sensitivity of the pacemaker's sensing features. An optional realtime
printout contains an amplitude annotation of the measured value in
each individual cycle.
Retrograde Conduction Test
Valid for Cylos
To measure the retrograde conduction time, an appropriate test
function is available at follow-up. During the test, the patient is paced
at an increased ventricular rate over several cycles while the VA interval
is measured. (This is the time between ventricular pacing and the
subsequent atrial sensing). The result is displayed as a minimum,
mean, and maximum value. An optional realtime printout contains an
amplitude annotation of the measured value in each individual cycle.
External Pulse Control (NIPS)
The pacemaker offers a high-speed digital communication mode that
enables the transmission of pacemaker pulses to be controlled with the
programmer.

116
Follow-up Options
Through its external pulse control function, the pacemaker can be used
as an "implanted electrophysiologic laboratory" for non-invasive
programmed stimulation (NIPS) and for terminating tachycardia. The
maximum pacing rate is 800 ppm for single-chamber operation
(corresponding to a minimum coupling interval of 75 ms).
Two operating modes are available:
• Burst stimulation with realtime control of the burst rate
• Programmed stimulation adjustable over a broad range with up to
four extrastimuli.
Caution!
External pulse control must be carried out bearing
the usual safety precautions in mind, because,
depending on the stimulation protocol and the
patient's condition, dangerous arrhythmia
including ventricular fibrillation and flutter may be
induced during any electrophysiological study. If
defibrillation becomes necessary, care should be
taken to place the leads so as to minimize the risk
of damage to the implanted pacemaker. Anterior
and posterior placement as far as possible from
the pacemaker is best.
Caution!
With high triggered rates, high pulse amplitude,
and large pulse width, a temporary decrease of the
pulse amplitude may occur. Therefore, the
effectiveness of the pacing pulses must be secured
by continuous ECG monitoring. After the
replacement indication has been reached, external
pulse control is blocked.
Temporary Program Activation
The pacemakers feature two program memories, one for the
permanent program and the other for a temporary program. This
makes it possible to temporarily activate complete programs during
follow-up. Temporary programs remain active only as long as the
programming head is positioned over the pacemaker and no other
program is being transmitted. As soon as the programming head is
removed, the temporary program is replaced by the permanent
program within one cycle. Programs containing a parameter conflict
cannot be transmitted as permanent programs, but can (with some
exceptions) be transmitted as temporary programs.

117
Follow-up Options
Temporary program activation facilitates a quicker and safer follow-up.
All test programs that could be hazardous to the patient should only be
activated temporarily. If a dangerous situation arises, the permanent
program can be reactivated immediately by removing the programming
wand. Temporary programming is also terminated by the following:
• Interrogating the implant
• Transmitting the magnet effect and patient data
• Saving the follow-up data in the implant
• Interrogating and beginning statistics
• Transmitting settings for statistics (AF/AFL range) and IEGM
recordings
If you want to have sensing intact during temporary programming, do
not program the magnet effect to "asynchronous."
When the pacemaker is interrogated, the permanent program is always
displayed, even while a temporary program is active. During magnet
application, i.e., during temporary program activation, the rate
adaptation and the event counters are always inactive.
Note:

If you are terminating a temporary program by
removing the programming head, make sure that
the distance between the programming wand and
the pacemaker is large enough (at least 10 cm or 4
inches). This is to ensure that the reed switch in
the magnet really opens.
118
Follow-up Options
Patient Data Memory
Individual patient data can be stored in the pacemaker. This data
includes the patient's name, patient code, symptoms, etiology, ECG
indication, implantation date, and lead polarity. The extent and type of
the stored data depends on the programmer software module being
used.
Storing Follow-up Data
Purpose
This function allows you to store up to 4 follow-ups in the implant. This
enables you to quickly detect the significant changes that occur
between the individual follow-ups.
Description
After interrogation of the implant, the stored follow-up data are
transmitted and can be displayed on the programmer. It is possible to
store data from the following follow-up tests:
—
Date of the individual follow-ups
—
Lead impedance in the atrium and ventricle
—
Lead polarity for all follow-up tests
—
The amplitudes of the P and R waves
—
Atrial and ventricular thresholds
—
Retrograde conduction time
—
Battery status
Position Indicator for the Programming Wand
The programmer indicates via a visual and audible signal when the
programmer head is in telemetry contact with the pulse generator. This
eases positioning of the programming wand.

119
Handling and Implantation
Handling and Implantation
Sterilization and Storage
The pacemaker and its accessories have been sterilized with ethylene
oxide gas. To guarantee sterility, the container should be checked for
damage before opening. If resterilization becomes necessary, contact
your local BIOTRONIK representative.
The pacemaker is shipped in a cardboard box equipped with a quality
control seal and an information label. The label contains the model
specifications, technical data, the serial number, expiration date, and
sterilization and storage information of the pacemaker. The box
contains the plastic container with the pacemaker and documentation
material.
Caution!
The pacemaker should only be stored at
temperatures between 5°C and 55°C (41°F to
131°F). Exposure to temperatures outside this
range may result in pacemaker malfunction.
Automatic Transportation Mode
The implant is shipped in transportation mode; ERI detection is
deactivated in this mode. ERI detection is automatically activated when
one of the following conditions occurs:
• Auto-initialization was successfully executed
• The programmer measures a lead impedance smaller than 3200
Ohm
• The pacemaker is stored for longer than 24 months
• The safe program was successfully transmitted

120
Handling and Implantation
Opening the Sterile Container
Caution!
Use only the BIOTRONIK screwdriver to connect
and loosen the screw in the connector block. If you
need to exchange a lead, order another sterile
screwdriver from BIOTRONIK.
For protection against mechanical jolting during transportation and to
preserve sterility, the pacemaker is packaged in two plastic containers,
one within the other. Each one is separately sealed and then sterilized
with ethylene oxide. This double packaging ensures the sterility of the
outer surface of the inner container which can, therefore, be directly
removed by the implanting physician.
Peel off the sealing paper of the non-sterile outer container in the
direction indicated by the arrow.
Remove the sterile inner container using the recessed grip and open it
by peeling the sealing paper in the direction indicated by the arrow.
Connecting the Leads
The pacemaker has been designed for and is recommended for use
with unipolar or bipolar leads with an IS-1 connector. Appropriate
adapters should be fitted when using electrodes with another
connection.
Caution!
When connecting unipolar leads to the pacemaker,
you must set the pacing and/or sensing function of
the respective channel to unipolar configuration.
In cases where you are replacing the pacemaker, make sure that the
leads and lead connectors are not damaged.

121
Handling and Implantation
If you cannot insert the lead connector completely, it may be that the
setscrew is projecting into the hole for insertion on the screw block.
Turn the setscrew counterclockwise with a screwdriver far enough to
allow you to insert the lead connector completely.
Caution!

To prevent cross threading, do not back the
setscrew all the way out of the threaded hole.
Leave the screwdriver in the slot of the setscrew as
you insert the lead.
122
Handling and Implantation
Connecting Cylos DR/DR-T with an IS-1 Connector
Insert the lead connector into the connector receptacle without
bending the lead until the connector pin becomes visible behind the set
screw block.
A: Using the screwdriver included, pierce the slot of the silicone plug
vertically and insert the blade of the screwdriver into the setscrew.
B: Tighten setscrew with the enclosed screwdriver clockwise until the
torque becomes limited (you will hear a crackling sound). Carefully
withdraw the screwdriver without turning back the setscrew.
When you withdraw the screwdriver, the silicone plug automatically
seals the lead connector block safely. The proximal pole of the bipolar
lead is automatically connected. Now attach the second lead connector
as described above.
Insert the non-absorbable fixation suture through the opening in the
lead connector block and fixate the pacemaker in the prepared pocket.

123
Handling and Implantation
Connecting Cylos VR with an IS-1 Connector
Insert the lead connector into the connector receptacle without
bending the lead until the connector pin becomes visible behind the
setscrew block.
A: Using the screwdriver included, pierce the slot of the silicone plug
vertically and insert the blade of the screwdriver into the setscrew.
B: Tighten setscrew with the enclosed screwdriver clockwise until the
torque becomes limited (you will hear a crackling sound). Carefully
withdraw the screwdriver without turning back the setscrew.
When you withdraw the screwdriver, the silicone plug automatically
seals the lead connector block safely. The proximal pole of the bipolar
lead is automatically connected.
Insert the non-absorbable fixation suture through the opening in the
lead connector receptacle and fixate the pacemaker in the prepared
pocket.

124
Handling and Implantation
Follow-up Basics
Follow-up lets you check the pacing system and optimize settings.
The likelihood of an electronic defect or a premature battery depletion
is extremely low. Pacing system malfunctions attributed to other
causes such as threshold increase are considerably more probable. In
most instances, they can be corrected by reprogramming the
pacemaker. The follow-up intervals are, therefore, primarily determined
by medical considerations, taking into account the patient's
dependency on the pacemaker.
The following notes are meant to stress certain product features of the
pacemaker that are of importance for the follow-up. For detailed
recommendations on the performance of follow-up tests and medical
considerations, please refer to the pertinent medical literature.
See the respective software module manual for a detailed description
of the procedure and for more information on the individual functions.
Note:
Only ECG devices that do not delay the display of
the ECG curve should be used for pacemaker
follow-up. Devices with such a delay (e.g., devices
with automatic base line adjustment) are
fundamentally unsuitable for pacemaker follow-up.
Battery Status
The replacement indication is reached when the pacing rate without
magnet application is 4.5 – 11% lower than the programmed basic
rate (depending on the selected mode).

125
Handling and Implantation
If the pacing rate only decreases when a magnet is applied, then the
replacement indication has not yet been reached but may be expected
shortly.
The replacement indication will also be displayed by the programmer
when interrogating the pacemaker and will appear in a data printout.
For a detailed description of the replacement indication and the
expected service times, please refer to the section entitled
"Replacement Indication."
The battery condition can also be tested by using analog data
telemetry. Nevertheless, the point of reference for replacement
indication is always the basic rate.
Activation of ERI Detection
ERI detection is automatically activated when one of the following
conditions occurs:
• Auto-initialization was successfully executed
• The programmer measures a lead impedance smaller than 3200
Ohm
• The pacemaker is stored for longer than 24 months
• The safe program was successfully transmitted
Testing the Pacing Threshold
To facilitate follow-up, the pacemakers feature a high-resolution
threshold test with a resolution of 0.1V in the range of 0.1V to 4.8V.
The ventricular threshold test can be performed manually or
automatically. The prerequisites for an automatic threshold test in the
ventricle are as follows:
—
A ventricular rate of < 100 bpm
—
Adequate signal quality
—
The implant is not set to mode switching
The pulse amplitude for the permanent program is selected based on
the measured threshold and under consideration of the safety margin.

126
Handling and Implantation
Sensing Functions
A measuring function for the P- and R-wave amplitudes is available for
testing the sensing function. This test measures the minimum, mean,
and maximum amplitude values over several cycles. An optional
realtime printout contains an amplitude annotation of the measured
value in each individual cycle.
Additionally, the pacemaker provides an intracardiac electrogram with
marker signals. The triggered pacing mode may also be selected, at
which the pacemaker triggers pacing pulses simultaneously with the
sensing events. This enables easy identification of sensed events in the
ECG.
Particularly with unipolar sensing, the sensing function should be
checked for susceptibility to interference from skeletal muscle
potentials. If “oversensing” occurs, reducing sensitivity (setting a
higher value) and/or programming the pacemaker to bipolar sensing (if
a bipolar lead is in place) should be considered.
Retrograde Conduction
Ventricular events that are not synchronized with the atrium (such as
VES) can be conducted to the atrium through retrograde conduction.
The sensing function in the atrium may result in a pacemakermediated tachycardia (PMT).
To prevent PMT, the pacemaker's atrial refractory period must be
longer than the sum of the AV delay and the retrograde conduction
period.
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127
Handling and Implantation
A measuring test is available for verifying the retrograde conduction
time. See also the "Follow-up Options" section.
If retrograde conduction is present, the measured times should be
nearly identical. If the measured conduction times vary significantly,
this may be due to unstable atrial sensing or the absence of
conduction.
Rate Adaptation
With rate adaptation enabled, the programmed values should be
checked during each follow-up visit to ensure their therapeutic
suitability for the individual patient. Any change in the patient's general
well-being and cardiac performance since the follow-up should be
taken into consideration. As during the initial programming of rateadaptive pacing, it is recommended that the sensor-mediated rate at
rest as well as during and following exertion be checked at follow-up.
The control parameters may require adjustment if significant changes
are detected. Ensure that the settings for maximum sensor rate, rate
increase, and rate decrease are always well tolerated by the patient.
The pacemaker's diagnostic memory functions may be used to monitor
the rate response of the sensor under conditions of normal daily
activities. Recording the sensor trend during an exercise test is
recommended during follow-up. This facilitates the simulation of
different sensor settings on the programmer’s screen. In this manner,
a repetition of the exercise test can be avoided.
The pacemaker's standard program includes sensor settings that are
appropriate for many patients. A non-rate-adaptive mode may be
programmed when you are in doubt as to whether certain settings are
appropriate for a specific patient. In this mode, the sensor rate is
recorded (sensor rate histogram and activity report) without being
activated.

128
Handling and Implantation
Sensor Gain
The sensor gain controls the change in pacing rate for a certain change
in workload detected by the sensor. An exercise test (such as walking)
is recommended in order to achieve a rate response proportional to
workload by optimizing the sensor gain. If the pacing rate is too high
for the specific amount of workload, the sensor gain should be
reduced. If the pacing rate is too low, a higher gain setting should be
selected. The sensor trend with rate forecast can be used to record the
pacing rate during exercise.
Additionally to the fixed sensor setting, an automatic sensor gain is
available.
Sensor Threshold
The sensor threshold controls the signal amplitude that has to be
exceeded to cause a rate increase. This parameter is meant to assure a
stable pacing rate at rest and to prevent rate increases at signal levels
not consistent with physical exertion.
The sensor threshold should be optimized after adjusting the sensor
gain.
If the patient does not have a stable pacing rate at rest, the sensor
threshold should be increased. If, however, the pacemaker tends to
respond only at higher workloads, a reduction of the sensor threshold
should be considered. The sensor trend with rate forecast can be used
to record the pacing rate during provocation tests.

129
Handling and Implantation
Note:
Values can only be selected for the sensor
threshold that are greater than those used in the
permanent program.
Battery, Pulse and Lead Data
Battery, pulse and lead data can be obtained non-invasively by means
of analog telemetry. These data contain important information about
the status of the pacing system. Therefore, they should be documented
at each follow-up examination.

130
Replacement Indication
Replacement Indication
The length of the period from beginning of service (BOS) until
replacement indication (ERI) is reached depends on several factors.
These include battery capacity, lead impedance, pacing program,
pacing to inhibition ratio, and the properties of the pacemaker circuit.
Expected Time Until ERI
In the course of the follow-up, the pacemaker displays the expected
value up until ERI, based on the permanent program. This value is
derived from the measured energy consumption of the battery. If
program parameters are modified, the remaining time until ERI for the
edited program is also displayed on the program screen. If the
remaining time until ERI falls under six months, an appropriate
message is displayed.
BOS
"Beginning of Battery is in good condition; normal follow-up.
Service"
ERI
"Elective
The replacement time has been reached. The
Replacement pacemaker must be replaced.
Indication"
EOS
"End of
Service"
End of service time with regular pacemaking activity.
Table 10: Operating status indications of the pacemaker
Elective Replacement Indicator (ERI)
The pacemaker indicates the elective replacement indication with a
defined drop in both the programmed basic rate and the magnet rate
(see Table 11).
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131
Replacement Indication
Magnet Effect
cycles 1-10 after magnet
application
after 10th cycle
automatic
asynchronous with 80 ppm
synchronous with basic rate
reduced by 4.5 - 11% a)
asynchronous
asynchronous with 80 ppm
asynchronous with 80 ppm
synchronous
synchronous with basic rate synchronous with basic rate
reduced by 4.5 – 11% a)
reduced by 4.5 – 11% a)
Table 11: Magnet response after reaching ERI
a)
The pacing rate decreases by 11% in the pacing modes DDD(R), DDT(R), DDT(R)/A,
DDT(R)/V, DOO(R), VDD(R), VDI(R), VDT(R), VVI(R), VVT(R), AAI(R), AAT(R), and
AOO(R). In the pacing modes DDI(R), DDI/T(R), DVI(R), and DVT(R) only the VA delay is
extended by 11% . This reduces the pacing rate by 4.5-11% , depending on the selected
AV delay.
In dual-chamber modes, the pacemaker switches to single-chamber
pacing when it reaches replacement indication. This replacement mode
varies according to the programmed pacing mode and is shown on the
programmer.
The replacement indication is also indicated by the programmer when
interrogating the pacemaker; it can then be printed out with the data.
The battery status can also be tested using analog telemetry.
Nevertheless, the reference for the replacement indication is always the
basic rate.
Deactivating Functions at ERI
The following functions are deactivated when ERI has been reached:
• Night program
• Rate adaptation
• Atrial overdrive pacing
• Rate hysteresis
• Rate fading
• Lead check
• Active capture control (ACC)
• AV hysteresis
• PMT protection
• Statistics are not continued
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132
Replacement Indication
Remaining Service Time after ERI
The following tables show the mean1 and minimum2 values for the
remaining service time between reaching the ERI (elective replacement
indication) and magnet rate after reaching replacement indication EOS
(end of service) for the standard program3 and a program with a higher
pulse energy.4
The data are based on a lead impedance of 500 Ohms, 100% pacing
and the data supplied by the battery manufacturer. These times are at
most 30% shorter at a lead impedance of 300 Ohms instead of 500
Ohms.
Cylos DR/DR-T
Beginning of
ERI to EOS
Expected times in DDDR mode
(in months)
Standard
Program
Program with
Higher Pulse
Energy
Mean Value
Minimum Value
Table 12: Expected service times for Cylos DR
Cylos VR
Beginning of
ERI to EOS
Expected times in VDDR mode
(in months)
Standard
Program
Program with
Higher Pulse
Energy
Mean Value
Minimum Value
Table 13: Expected service times for Cylos VR
Note:
The expected service times could differ from those
given here if program settings are different from
those listed in the above tables.
50% of the pacemakers reach or exceed these values
99.9% of the pacemakers reach or exceed these values
Pulse amp. A/V 3.6 V, pulse width A/V 0.4 ms, rate 60 ppm
Pulse amp. A/V 4.8 V, pulse width A/V 1.0 ms, rate 90 ppm

133
Cautionary Notes
Cautionary Notes
The pacemaker, the lead(s), and, if used, the lead extensions and
adapters, become part of the artificial pacing system upon
implantation. The functioning of the artificial pacing system depends
on all these components, as well as the physiologic condition of the
patient.
The following notes are intended to emphasize some aspects that have
been deemed especially important in the medical literature for
evaluating and avoiding risks. This information could be useful in
evaluating and avoiding risks, but it is not a substitute for the study of
medical literature.
Medical Complications
Possible medical complications of cardiac pacemaker therapy include
the following: necrotic tissue formation, thrombosis, embolisms,
elevated pacing thresholds, foreign body rejection phenomena, cardiac
tamponade, muscle/nerve stimulation, infection, and pacemakerinduced arrhythmias (some of which could be life-threatening, such as
ventricular fibrillation).
Technical Malfunctioning
Events that could compromise functioning are, for example: a defect in
one of the pacemaker components, battery depletion, lead dislocation,
lead fracture, or an insulation defect.
Muscle Potentials
The filter properties of BIOTRONIK pacemakers have been adjusted to
the rate spectrum of cardiac actions, so the risk of sensing skeletal
muscle potentials is low. However, this risk cannot be completely ruled
out, especially not in unipolar systems and at a high pacemaker
detection sensitivity. If the pacemaker senses skeletal myopotentials as
intrinsic cardiac activity, then inhibition or asynchronous and/or
triggered pacing may result, depending on the pacing mode and the
interference pattern. You can test the whether the pacing system
functioning is safe from skeletal myopotentials, for example, by
monitoring the Holter or pacemaker performance while the patient
does movements involving chest muscles.

134
Cautionary Notes
To avoid skeletal myopotentials interfering with pacemaker functioning,
a lower sensitivity (a higher value), bipolar sensing, or a different
pacing mode can be programmed, depending on the availability of
these features.
Electromagnetic Interference (EMI)
Every implanted pacemaker can be affected by interference with
signals that the pacemaker sees as intrinsic cardiac activity and/or
that compromise measurements the pacemaker uses for rate
adaptation. Depending on the pacing mode and the type of
interference, these sources of interference may lead to pacemaker
pulse inhibition or triggering, an increase in the sensor-dependent
pacing rate, or a fixed-rate pulse delivery. Under unfavorable
conditions, for example during diagnostic or therapeutic procedures,
the interference sources may induce such a high level of energy into
the artificial pacing system that the pacemaker and/or cardiac tissue
around the lead tip is damaged.
BIOTRONIK pacemakers have been designed so that their susceptibility
to EMI is minimized. However, due to the variety and intensity of EMI,
absolute safety is not possible.
It is generally assumed that EMI produces only minor symptoms, if
any, in pacemaker patients.
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135
Cautionary Notes
If interference is expected to have clinically relevant consequences, the
patient must be protected from the interference or its effects, e.g.,
through appropriate warnings or pacemaker reprogramming.
Household Appliances
Electrical household appliances (e.g., ranges, microwave ovens, radios,
televisions, VCRs, electric shavers and toothbrushes) do not normally
affect pacemaker operation if the appliances are in good condition and
properly grounded and insulated. Simple electrical tools, such as drills
and battery-operated screwdrivers, are to be kept at a distance of at
least 12 inches (30 cm) from the pacemaker.
Cellular Phones
The possible influence of cellular phones on cardiac pacemakers
cannot be ruled out. Therefore, the patient should always hold the
cellular phone to the ear that is located on the opposite side of the
body from where the pacemaker was implanted. Some cellular phones
emit signals even when they are not turned on and are only on standby.
For this reason, cellular phones should not be carried at chest level. As
a rule, possible interference is only temporary, and the pacemaker will
again function properly once the cell phone is out of the immediate
vicinity of the implant. We recommend a minimum distance of 6 inches
(15 cm) to the implant.
Note:

When pacemaker sensitivities between 0.1 and 0.3
mV have been programmed, a distance of 8 inches
(20 cm) is recommended.
136
Cautionary Notes
Interference Due to Strong Electromagnetic Fields
To assess the potential for interference, medical advice must be
sought, especially in case of strong electromagnetic fields such as
those stemming from the following: electric arc welders; electric
melting furnaces; radio, radar, and television transmitters; power
plants; exposed ignition systems (e.g., internal combustion engines);
electrical tools; high-voltage power lines; and defective electrical
equipment that is not properly grounded or sufficiently insulated.
Anti-Theft Installations
Anti-theft installations used in department stores, libraries, or other
places can in rare cases interfere with pacemaker functioning. The
general recommendation is to pass quickly through such anti-theft
installations.
Risky Therapeutic and Diagnostic Procedures
Before using any of the following procedures, the benefits should be
thoroughly weighed against the risks. After performing any of these
procedures, the pacemaker function and pacing threshold must be
thoroughly checked.
Caution!

Some of the following procedures may cause latent
damage to the pacemaker. This damage may not
be detected when testing the pacemaker after the
procedure. However, these may lead to pacemaker
malfunctions at a later time, and in extreme cases
to pacemaker failure.
137
Cautionary Notes
Caution!
Diathermy, transcutaneous nerve stimulation,
magnetic resonance imaging, and electrocautery
have been reported to interfere with
electromyographic monitoring. Cardiac activity
during any of these procedures should therefore be
monitored by additionally taking the patient's
peripheral pulse or blood pressure.
Defibrillation
The circuitry of BIOTRONIK pacemakers is protected against the
energy normally induced by defibrillation. Nevertheless, complete
protection is not possible. Any implanted pacemaker can be damaged
by defibrillation. Circumstances permitting, the following precautions
should be taken:
—
The paddles should be in an anterior-posterior position or
perpendicular to the axis formed by the pacemaker and the
heart.
—
The energy setting should not be higher than necessary for
defibrillation.
—
The distance between the defibrillator paddles and the
pacemaker and the implanted lead should be at least 10 cm (4
inches).
After defibrillation, the pacemaker function and pacing threshold must
be checked and monitored for a sufficient time period.
Interaction with an Implantable Cardioverter- Defibrillator(ICD)
When implanting both an ICD and a pacemaker with bipolar pacing,
the tip electrodes should be positioned as far apart as possible.
Appropriate testing must ensure that the functioning of the one device
cannot interfere with the other. Such testing will include, among other
things:
—
Test the arrhythmia detection function of the ICD while the
pacemaker is pacing. To do so, set the most unfavorable
combination, depending on the parameters set, with relation to
the pacing mode, the rate, and pulse energy.
—
Test the pacemaker's functions after delivery of a maximum
energy shock from the ICD.

138
Cautionary Notes
Ultrasound Therapy and Diathermy
As a rule, ultrasound therapy and diathermy are fundamentally
contraindicated for pacemaker patients due to possible heat build-up
in the implant. If a therapy must be performed, it should not be
applied in the immediate vicinity of the pacemaker or the lead. The
peripheral pulse of the patient should be continuously monitored
during treatment. The pacemaker function and pacing threshold must
be checked after the therapy.
Radiation Therapy
The electronic circuit elements of the pacemaker can be damaged by
radiation therapy. The pacemaker should be shielded during such
treatment. Following the radiation treatment, the pacemaker function
must be checked and monitored for a sufficient period of time.
Transcutaneous Electrical Nerve Stimulation(TENS)
This therapy is contraindicated for pacemaker patients. If the therapy
must be used, the following precautions are recommended:
—
The TENS electrodes should be placed as close as possible to
each other to reduce the spread of electricity.
—
The TENS electrodes should be placed as far away as possible
from the pacemaker and the lead.
—
Cardiac activity and the peripheral pulse should be monitored
during the nerve stimulation.

139
Cautionary Notes
After stimulation, the pacemaker function and pacing threshold must
be checked. For home use, the electrode positioning and current
strength settings must be such that the nerve stimulation does not
interfere with pacemaker functioning.
Magnetic Resonance Imaging (MRI)
This diagnostic procedure is contraindicated for pacemaker patients,
because a variety of complications may result, e.g., repositioning;
pulse inhibition; asynchronous and/or triggered pacing—depending on
the pacing mode and the interference pattern of the implanted
pacemaker—; damage to the circuitry; tissue damage in the vicinity of
the pacemaker and/or tip electrode; and lead dislocation.
If this procedure cannot be avoided, the patient and his/her peripheral
pulse must be constantly monitored. After an MRI, the pacemaker
function and pacing threshold must be checked and monitored for a
sufficient period of time.
Lithotripsy
This treatment is contraindicated for pacemaker patients because
electrical and/or mechanical interference with the pacemaker is
possible. If it must be used, the selected site for electrical and
mechanical stress should be as far away as possible from the
pacemaker. The patient's peripheral pulse should be continuously
monitored throughout the treatment. After the procedure, the
pacemaker function must be checked and monitored for a sufficient
period of time.

140
Cautionary Notes
Electrocautery
Electrocautery should never be performed within 15 cm (6 inches) of
an implanted pacemaker or lead because of the danger of inducing
ventricular fibrillation and/or damaging the pacemaker. For
transurethral electroresection of the prostate, placing the neutral
electrode under the buttocks or around the upper thigh, but not in the
thoracic area, is recommended. The pacemaker should be
programmed to an asynchronous mode to avoid inhibition by
interference signals. The patient's peripheral pulse should be
continuously monitored throughout the treatment. The pacemaker
function must be checked after the treatment.
Hyperbaric Oxygen Therapy
In-vitro tests conducted to date have not yielded any results of
compromised pacemaker and lead functioning if the hyperbaric
pressure does not exceed 1.5 bar (2.5 bar absolute). At higher
pressures, deformation of the pacemaker housing was observed.
However, until these test results can be clinically confirmed with
statistically significant case data, hyperbaric oxygen therapy is
contraindicated regardless of the pressure applied, because the
environmental conditions entailed in this therapy are out of the defined
range of use.
If this procedure cannot be avoided, the hyperbaric pressure must
absolutely not exceed 1.5 bar (2.5 bar absolute), and the patient must
be continually monitored. After the procedure, the pacemaker and the
artificial pacing system must be checked and observed for a sufficient
period of time.

141
Cautionary Notes
Explantation
Explanted pacemakers can be sent to the local BIOTRONIK
representative for proper, environmentally friendly disposal. Before
returning it, the explanted pacemaker should be cleaned with a sodium
hypochlorite solution containing at least 1% chlorine and then
thoroughly washed with water, if possible. The pacemaker should be
explanted before a deceased pacemaker patient is cremated.

142
Technical Data
Technical Data
Pacing Modes
Cylos DR
DDD-CLS, VVI-CLS, DDDR, DDTR/A, DDTR/V, DDTR,
DDIR, DDIR/T, DVIR, DVTR, D00R, VDDR, VDTR,
VDIR, VVIR, VVTR, V00R, AAIR, AATR, A00R
DDD, DDT/A, DDT/V, DDT, DDI, DDI/T, DVI, DVT,
D00, VDD, VDT, VDI, VVI, VVT, V00, AAI, AAT, A00,
OFF
DDD(R) +, DDT/A(R) +, DDT/V(R)+ , AAI(R) +, AAT(R) +
Cylos VR
VVI-CLS, VVIR, VVTR, V00R, VVI, VVT, V00, OFF
Valid for
Cylos DR-T
Home Monitoring is possible for the following modes:
DDD(R) , DDT(R)/A, DDT(R)/V, DDT(R), DDI(R),
DDI(R)/T, VDD(R), VDT(R), VVI(R),VDI(R), DDD(R)+,
DDT(R)/A+,
DDT(R)/V+; DDD-CLS; VVI-CLS
Home Monitoring — Programmable Parameters
Valid for Cylos DR-T
Home Monitoring
Off, On
Monitoring Interval
1 day
Time of Trend Message
Between 0:00 (12:00 a.m.)
...(10)...
and 23:50 (11:50 p.m.)
Patient Message
Off, On
Event Message
Off, On
Home Monitoring –
Non-Programmable Parameters/Value Ranges
Valid for
Cylos DR-T
For Home Monitoring, stored data and events are displayed under the
following topics:
—
Stored Messages
—
Atrial Rhythms
—
Ventricular Rhythms
—
System Status
Stored Messages
The following are displayed:
—
Type and time of last message
—
Elapsed time in days
—
Number of trend messages
—
Number of patient messages

143
Technical Data
Atrial Rhythms
Mean Value AES
0; 1...(10); > 10; > 100
Number of Atrial
Tachycardias (AT)
0; 1...(10); > 10; > 20
Number of Atrial
Fibrillation (AF)
0; 1...(10); >10; > 20
Number of Atrial
Flutter (AFl)
0; 1...(10); > 10; > 20
AV Synchrony
(Ax Vx/Vx)
0; 3...(3)...100%
Number of
Tachycardia
Episodes
0 ... (1)...10...(2)...60; > 60
Duration of
Tachycardia
Episodes
0; 3...(3) ...100%
Ventricular Rhythms
Mean Ven. Heart
Rate
< 50; 52; ...(2)...174; > 174 bpm
Max. Ven. Heart
Ratea)
< 85; 85;)...248; > 248 bpm
Duration of Max.
Ven. Heart Ratea)
< 0.5; 0.5 ...1.0; 1.0 ...2.0; 2.0 ...2.5;  5 min
Max. Ven. Heart Rate < 120;  120;  140;  160;  180;  200;  220 bpm
during Tachycardia
Episodesb)
Number of
Max. VES/h
0;1...10; 11...30; > 30
Number of Ven.
Runs
0; 1; 2; (1)...10; > 10
Number of Ven.
Episodes (VT)
0; 1; 2; > 2
a) Captured by IEGM recording during high ventricular rates
b) Captured by IEGM recording of Mode Switching
System Status
Atrial/Ven. Lead
Check
OK; not OK a) ,
(if not OK, then switch from bipolar to unipolar)
Mean P/R-Wave
Amplitude
No measurement b);
< 50% a) ; 50 - < 100%;  100% safety margin
(Battery) Status ERI
OK; ERI active a)
a) Parameter value triggers event report
b) Or the measurement is below the programmed sensitivity

144
Technical Data
Active Capture Control (ACC)
Status Amplitude
Control (ACC)
On; Off; Deactivated
Ventricular
Thresholds
< 0.3;  0.3;  0.5;... (0.2) ...  4.7;  4.8
Pulse and Timing Parameters1
Cylos DR/DR-T
Basic Rate a), b)
30 ... (1) ... 88 ... (2) ... 122 ... (3) ... 140 ... (5) ...
180 ppm
Night Program
Rate Hysteresis
off; on
a)
Repetitive rate
hysteresis
off; -5 ... (5) ... -50 bpm
off; 1 ... (1) ... 10
Scan rate hysteresis off; 1 ... (1) ... 10
Upper Tracking Rate 100; 110; 120; 130; 140; 160; 185 ppm
(UTR) a)
Tachycardia Mode
2:1; WRL (automatic adjustment)
Runaway
protection a), c)
195 ... 220 ppm
Dynamic AV Delay
Off, low; medium; high; individual; fixed
AV Delay Values
15; 50; 75; 100; 120 ... (10) ... 200; 225; 250; 300
ms (programmable in 5 ranges)
AV hysteresis
Off; low; medium; high; negative
AV Repetitive
Hysteresis
Off; 1...(1)...6
AV Scan Hysteresis
Off; 1...(1)...6
Repetitive Negative
AV Hysteresis
1...(1)...10...(3)...100...(10)...180
Sense Compensation Off, -15 ... (-15) ... -120 ms
AV Safety Delay
100 ms
Atrial Blanking
Period
32; 40; 48; 56; 72 ms
Far- Field Blanking
56...(25)...200 ms
Ventricular blanking
period d)
16; 24; 32; 40; 48; 56; 72 ms
Magnet Effect
auto; asynchronous; synchronous
37°C, 500 

145
Technical Data
Cylos DR/DR-T
Pulse amplitude A
Pulse amplitude V
0.1 ...(0.1) ... 4.8 ... (0.6) ... 8.4 V
0.1 ... (0.1) ... 4.8 ... (0.2) ... 8.4 V
Pulse width A
Pulse width V
0.1; 0.2; 0.3; 0.4; 0.5; 0.75; 1.0; 1.5 ms
0.1; 0.2; 0.3; 0.4; 0.5; 0.75; 1.0; 1.5 ms
Sensitivity A
Sensitivity V
0.1 ... (0.1) ... 1.5 ... (0.5) ... 7.5 mV
0.5 ... (0.5) ... 7.5 mV
Refractory period A
Refractory period V
200 ... (25) ... 775 ms
170; 195; 220; 250; 300; 350; 400 ms
Atrial refractory
period extension
0 ... (50) ... 350 ms
Tachycardia
behavior
Off, Mode Conversion, Mode Switching
Mode conversion
Off; On (in modes DDD(R), DDT(R)/A, DDT(R)/V, and
VDD(R))
Mode switching
Off; On (in modes DDD(R), DDT(R)/A, DDT(R)/V,
DDD(R) +, DDT/A(R) +, DDT/V(R)+ and VDD(R))
Intervention rate
110...(10)...250 ppm
X-out-of-8 criterion
3...(1)...8
Z-out-of-8 criterion
3...(1)...8
Basic Rate during
Mode Switching
+5...(5)...+30 ppm
2:1 Lock-in
Protection
On; Off
PMT Management
Off; On
VA Criterion
250...(10)...500 ms
Overdrive Mode
Off; On
Max. Overdrive Rate
100...(10)...160 ppm
Levels of Overdrive
Pacing (for Rate
Increase)
low; medium; high
Overdrive pacing
1...(1)...32 cycles
plateau (the rate
decrease thereafter)
Min. PVARP
Off; On
Lead configuration
for
A/V pacing
A/V sensing
unipolar; bipolar / unipolar; bipolar
unipolar; bipolar / unipolar; bipolar
Autom. lead
monitoring
Off; On
Active capture
control (ACC)
On; Off; ATM
Minimum Ventricular 0.2...(0.1)...3.6...(0.1)...4.8 V
Amplitude
Maximum
Ventricular
Amplitude

2.4; 3.6; 4.8; 6.4 V
146

Technical Data
147
Technical Data
Cylos DR/DR-T
Scan Period
Intervals; Times of Day
Intervals
every 0.1; 0.3; 1; 3; 6; 12; 24 hours
Times of Day,
the 1st/2nd Time of
Day
0:00 to 24:00 hours
Safety Margin
0.3...(0.1)...(0.5) ...(0.1)...1.2 V
Auto-Initialization
Off; Lead Detection; On
VES Lock-in
Protection
On; Off
Termination after
4; 6; 12 cycles
a)
The corresponding intervals (t) correlate with the rates (r) according to the formula
t = 60,000 / r (where t is in ms, r in ppm)
b) The values 30, 31, 32, 33, and 34 are for temporary settings only.
c) In the event of an electronic defect
d) The values depend on the atrial blanking period set
Cylos VR
Basic rate a), b)
30 ... (1) ... 88 ... (2) ... 122 ... (3) ... 140 ... (5) ...
180 ppm
Night Program
Rate Hysteresis
Off; On
a)
Repetitive rate
hysteresis
off; -5 ... (5) ... -80 bpm
off; 1 ... (1) ... 10
Scan rate hysteresis off; 1 ... (1) ... 10
Upper Tracking Rate 100; 110; 120; 130; 140; 160; 185 ppm
(UTR) a)
Tachycardia Mode
2:1; WRL (automatic adjustment)
Runaway
protection
195 ... 220 ppm
a), c)
Dynamic AV Delay
low; medium; high; individual; fixed
AV Delay Values
15; 50; 75; 100; 120 ... (10) ... 200; 225; 250; 300
ms (programmable in 5 ranges)
AV hysteresis
Off; low; medium; high; negative
AV Repetitive
Hysteresis
Off; 1...(1)...6
AV Scan Hysteresis
Off; 1...(1)...6
Negative AV
Hysteresis
1...(1)...10...(3)...100...(10)...180
Magnet Effect
auto; asynchronous; synchronous
Atrial Blanking
Period
32; 40; 48; 56; 72 ms
Far- Field Blanking
56...(25)...200 ms
Pulse Amplitude V
0.1 ... (0.1) ... 4.8 ... (0.2) ... 8.4 V
Pulse Width V
0.1; 0.2; 0.3; 0.4; 0.5; 0.75; 1.0; 1.5 ms

148
Technical Data
Sensitivity A
Sensitivity V
0.1 ... (0.1) ... 1.5 ... (0.5) ... 7.5 mV
0.5...(0.5)...7.5 mV
Cylos VR
Refractory period A
Refractory period V
200 ... (25) ... 775 ms
170; 195; 220; 250; 300; 350; 400 ms
Atrial Refractory
Period Extension
0 ... (50) ... 350 ms
Tachycardia
Behavior
Off, Mode Conversion, Mode Switching
Mode conversion
Off; On (in mode VDD(R))
Mode Switching
Off; On (in mode VDD(R))
Intervention Rate
180...(10)...250 ppm
X-out-of-8 Criterion
3...(1)...8
Z-out-of-8 Criterion
3...(1)...8
Basic Rate during
Mode Switching
+5...(5)...+30 ppm
2:1 Lock-in
Protection
On; Off
PMT Management
Off; On
VA Criterion
250...(10)...500 ms
Min. PVARP
Off; On
Lead configuration
for
V pacing
A sensing
V sensing
unipolar; bipolar
bipolar
unipolar; bipolar
Automatic Lead
Monitoring
Off; On
Active capture
control (ACC)
On; Off; ATM
Minimum Ventricular 0.2...(0.1)...3.6...(0.1)...4.8 V
Amplitude
Maximum
Ventricular
Amplitude
2.4; 3.6; 4.8; 6.4 V
Scan Period
Intervals; Times of Day
Intervals
every 0.1; 0.3; 1; 3; 6; 12; 24 hours
Times of Day,
the 1st/2nd Time of
Day
0:00 to 24:00 hours
Safety Margin
0.3...(0.1)...(0.5) ...(0.1)...1.2 V
Auto-Initialization
Off; Lead Detection; On
VES Lock-in
Protection
On; Off
Termination after
4; 6; 12 cycles
a)

The corresponding intervals (t) correlate with the rates (r) according to the formula
t = 60,000 / r (where t is in ms, r in ppm)
149
Technical Data
b) The values 30, 31, 32, 33, and 34 are for temporary settings only.
c) In the event of an electronic defect

150
Technical Data
Rate Adaptation
Cylos DR/DR-T/VR
Max. (sensor or)
activity rate a)
80...(5)...180 ppm
Sensor Gain
auto; 1 ... 40 (in 32 steps)
Automatic Sensor
Gain
Off; On
Sensor Threshold
Very Low; Low; Medium; High; Very High
Rate Increase
1; 2; 4; 8 ppm/cycle
Rate Decrease
0.1; 0.2; 0.5; 1.0 ppm/cycle
Rate fading
On; Off
R Rate Increase
1; 2: 4; 8 ppm/cycle
R Rate Decrease
0.1; 0.2; 0.5; 1.0; 1.2 ppm/cycle
a)
In DDIR and DVIR modes for Cylos DR (partially due to the AV delay selected) and VVIR
and VOOR modes in Cylos in general, there are lower maximum sensor rates than
stated here. The programmer will show the respective values.
CLS Parameters
Cylos DR, Cylos DR-T, Cylos VR
Maximum CLS rate
80 ... (5) ... 160 ppm
Additional
parameters
CLS dynamics (very low; low; medium; high; very high)
Dynamic runaway protection (on; off) a)
VP is required (yes; no)
a)

The pacing rate attained at rest is calculated from the following formula:
basic rate + 20 ppm + 1/8 (basic rate – Closed Loop rate).
151
Technical Data
Parameters at Replacement Indication
Basic Rate
Programmed value minus 11% (minus 4.5 - 11% in
modes DVI(R), DDI(R), DVT(R), and DDI/T(R),
depending on the programmed AV delay)
Magnet Rate
80 ppm for 10 cycles directly after magnet application
(not so in synchronous magnet mode)
Pulse Width
Programmed values
Pulse amplitudes
– programmed values with ACC deactivated (Off)
– last measured threshold + 1.2 V with ACC activated
(On) before ERI was reached
Sensitivity
Programmed values

152
Technical Data
Additional Functions
Cylos DR/VR
—
—
—
—
—
—
—
—
—
—
—
—
Automatic Amplitude Control (ACC)
Automatic Initialization
Automatic Lead and Polarity Detection
IEGM Recordings
Preventive Atrial Overdrive Pacing1
Tachycardia Behavior
— Automatic Mode Conversion
— X/Z-out-of-8 Mode Switching with 2:1-Lock-In Protection
PMT Management
VES Lock-in Protection
Rate Fading
Dual-channel IEGM with Event Markers
AV Hysteresis
— AV Scan and AV Repetitive Hysteresis
— Negative AV Hysteresis
Storage of Follow-up Data in the Implant
Cylos DR-T
Same range of functions as Cylos DR, and additionally:
—
Home Monitoring
Cylos VR
—
—
—
—
—
—
—
Automatic Amplitude Control (ACC)
Automatic Initialization
Automatic Lead and Polarity Detection
IEGM Recordings
Automatic Lead Check
Rate Fading
Storage of Follow-up Data in the Implant
Valid for Cylos DR-T and Cylos DR only.

153
Technical Data
Default Programs
Cylos DR/DR-T
Parameter/Function Factory Settings Standard
Program
Safe Program
Mode
DDD
DDD
VVI
Basic rate
60 ppm
60 ppm
70 ppm
Night program
Off
Off
Off
Rate hysteresis
Off
Off
Off
Repetitive rate
hysteresis
—
—
—
Scan rate hysteresis —
—
—
Upper tracking rate
130 ppm
130 ppm
—
Dynamic AV delay
Low
Low
—
AV hysteresis
off
off
—
Repetitive AV
Hysteresis
—
—
—
AV Scan Hysteresis
—
—
—
Sense compensation -45 ms
-45 ms
—
AV safety delay
100 ms
100 ms
—
Atrial blanking
period
56 ms
56 ms
—
Ventr. blanking
period
32 ms
32 ms
—
Magnet effect
Asynchronous
Auto
Auto
Pulse amplitude A
Pulse amplitude V
3.6 V
3.6 V
3.6 V
3.6 V
—
4.8 V
Pulse width A
Pulse width V
0.4 ms
0.4 ms
0.4 ms
0.4 ms
—
1.0 ms
Sensitivity A
Sensitivity V
1.0 mV
2.5 mV
1.0 mV
2.5 mV
—
2.5 mV
Refractory period A
Refractory period V
425 ms
250 ms
425 ms
250 ms
—
300 ms
Atr. refractory per.
ext.
0 ms
0 ms
—
Mode conversion
off
off
—
Mode Switching
off
on
—
X-out-of-8 Criterion
—
5-out-of 8
—
Z-out-of-8 Criterion
—
5-out-of 8
—

154
Technical Data
Parameter/Function Factory Settings Standard
Program
Safe Program
Intervention Rate
—
160
—
Far-Field Blanking
56 ms
56 ms
—
Switch to
—
DDIR
—
Basic Rate during
Mode Switching
—
+ 10
—
2:1 Lock-in
Protection
off
off
—
VES lock-in
protection
off
off
—
Min. PVARP
235 ms
235 ms
—
Sensor Threshold
—
—
—
Sensor Gain
—
—
—
Autom. sensor gain
—
—
—
Rate Increase
—
—
—
Max. Activity Rate
—
—
—
Rate Decrease
—
—
—
Rate Fading
off
off
off
RF Rate Increase
—
—
—
RF Rate Decrease
—
—
—
Pace A/V
unipolar
unipolar
unipolar
Sense A/V
unipolar
unipolar
unipolar
PMT Management
off
on
—
VA Criterion
—
380 ms
—
Autom. Lead
Monitoring A/V
off
off
off
Auto-Initialization
on
—
—
ACC
off
ATM
off
Max. Amplitude
—
3.6 V
—
Scan Time
—
at intervals
—
Interval
—
12 hours
—
Lead Configuration
Cylos VR
Parameter/Function Factory Settings Standard
Program
Safe Program
Mode
VDD
VDD
VVI
Basic Rate
60 ppm
60 ppm
70 ppm
Night Program
off
off
off

155
Technical Data
Rate hysteresis
off
-10 ppm
Parameter/Function Factory Settings Standard
Program
off
Safe Program
—
off
—
Scan rate hysteresis —
off
—
Upper tracking rate
130 ppm
130 ppm
—
Dynamic AV Delay
Low
Low
—
AV hysteresis
off
off
—
AV Repetitive
Hysteresis
—
—
—
AV Scan Hysteresis
Repetitive rate
hysteresis
—
—
—
Sense compensation —
—
—
AV safety delay
—
—
—
Atrial blanking
period
56 ms
56 ms
—
Magnet effect
Auto
Auto
Auto
Pulse amplitude V
3.6 V
3.6 V
4.8 V
Pulse width V
0.4 ms
0.4 ms
1.0 ms
Sensitivity A
Sensitivity V
0.2 mV
2.5 mV
0.2 mV
2.5 mV
—
2.5 mV
Refractory Period A
Refractory Period V
425 ms
250 ms
425 ms
250 ms
—
300 ms
Atrial Refractory
Period Extension
0 ms
0 ms
—
Mode conversion
off
off
—
Mode Switching
off
on
—
X-out-of-8 Criterion
—
5-out-of 8
—
Z-out-of-8 Criterion
—
5-out-of 8
—
Intervention Rate
—
160
—
Far-Field Blanking
56 ms
56 ms
—
Switch to
—
VDIR
—
Basic Rate during
Mode Switching
—
+ 10
—
2:1 Lock-in
Protection
off
off
—
VES lock-in
protection
off
off
—
Min. PVARP
235 ms
235 ms
—
Sensor Threshold
—
Medium
—
Tachycardia Behavior

156
Technical Data
Sensor Gain
—
—
Autom. Sensor Gain
—
on
—

157
Technical Data
Parameter/Function Factory Settings Standard
Program
Safe Program
Rate Increase
—
2 ppm/s
—
Max. Activity Rate
—
120 ppm
—
Rate Decrease
—
0.5 ppm/s
—
Rate Fading
off
off
off
RF Rate Increase
—
—
—
RF Rate Decrease
—
—
—
Pacing V
unipolar
unipolar
unipolar
Sensing A/V
bipolar/
unipolar
bipolar/
unipolar
—/
unipolar
PMT Management
off
on
—
VA Criterion
—
380 ms
—
Autom. Lead
Monitoring A/V
off
off
off
Auto-Initialization
on
—
—
ACC
off
ATM
off
Max. Amplitude
—
3.6 V
—
Scan Period
—
at intervals
—
Interval
—
12 hours
—
Lead Configuration
Materials in Contact with Human Tissue
Housing
titanium
Seals
silicone
Connector block
epoxy resin
Coating (if used)
silicone
Programmer
ICS 3000, PMS 1000plus, PMS 1000 C, PRT 1000,
TMS 1000plus, TMS 1000

158
Technical Data
Electrical Data1
Cylos DR-T/DR/VR
Circuit
hybrid electronics with VLSI-CMOS chip
Input impedance A
Input impedance V
> 10 kOhm
> 10 kOhm
Waveform
biphasic, asymmetric
Polarity
cathodic
Power consumption
DR/DR-T
SLR
BOS, inhibited
13 µA
13 µA
13 µA
21 µA
BOS, 100% pacing
21 µA
21 µA
Surface area of
housing that is
electrically
conductive
uncoated:
coated:
32.8 cm 2
7.23 cm 2
Shape of housing
that is electrically
conductive
uncoated:
coated:
flattened ellipsoid
elliptical
Battery
Type
Li/I
Manufacturer
Wilson
Greatbatch
or
Litronik
Model
WG 8431 or
LIS 3150
No-load voltage
Nominal capacity
a)
2.8 V
a)
1.3 Ah
Information from the battery manufacturers
Service Times
Service Times (in years) a)
DR/DR- VR
Nominal service time b)
for pulse amplitudes of 3.6
tbd
tbd
Expected service time c)
for pulse amplitudes of 3.6
tbd
tbd
Remaining capacity at ERI
(in Ah)
tbd
tbd
a)
Other parameters such as the standard program, 100% pacing, are calculated using
data from the battery manufacturers.
b) Calculated using the formula: T = 2740 x Cbat / (IBOS + IEOS)
37°C, 500 

159
c)
Technical Data
Anticipated service times taking all available data into consideration
Mechanical Data
Cylos
DR
Cylos DR-T
Lead connection
IS-1 (accepts unipolar and bipolar)
Weight
26 g
27 g
Volume
10 cm
Dimensions
6 x 42 x 51 mm
Storage Conditions
Relative
Humidity
max. 70%
Temperature
5 ... 55 °C
Pressure
0.7 ... 1.5 bar
X-ray Identification
RZ

12 cm
Cylos VR
24 g
6 x 44 x 51 mm
9 cm 3
6 x 39 x 51 mm
160
Technical Data
Projected Tolerances of Factory Settings1
Data according to EN 455002-2-1
Cylos DR/DR-T
Basic rate
Interference rate
60 ± 1.5 min-1
Basic Interval
1000 ± 20 ms
Escape Interval
1000 ± 20 ms
Magnet Rate
90 ± 3 min-1 (for 10 cycles)
Magnet Interval
664 ± 20 ms (for 10 cycles)
AV Delay
Basic rate
70 ppm
70-90 ppm
91-110 ppm
111-130 ppm
130 ppm
180
180
160
140
120
100
Pulse Amplitude
maximum value
EN 455002-2-1
mean value
+15/-5
+15/-5
+15/-5
+15/-5
+15/-5
+15/-5
ms
ms
ms
ms
ms
ms
Atrium
Ventricle
3.6 +0.1/-0.7
3.6 +0.1/-0.7
3.3 +0.1/-0.7
3.3 +0.1/-0.7
Pulse width
0.42 ± 0.02 ms
0.42 ± 0.02 ms
Sensitivity
15 ms sin2
40 ms sin2
1.0 ± 0.5 mV
2.5 ± 0.5 mV
EN 455002-2-1
delta pulse
1.8 ± 0.5 mV
Refractory period
425 +10/-20 ms
Runaway protection
2.5 ± 0.5 mV
-1
200 +20/-5 min
250 +10/-20 ms
200 +20/-5 min-1
Cylos VR
Basic rate
Interference rate
60 ± 1.5 min-1
Basic Interval
1000 ± 20 ms
Escape Interval
1000 ± 20 ms
Magnet Rate
90 ± 3 min-1 (for 10 cycles)
Magnet Interval
664 ± 20 ms (for 10 cycles)
37°C, 500 

161
Technical Data
Cylos VR
AV Delay
Basic rate
70 ppm
70-90 ppm
91-110 ppm
111-130 ppm
130 ppm
180
180
160
140
120
100
+15/-5
+15/-5
+15/-5
+15/-5
+15/-5
+15/-5
ms
ms
ms
ms
ms
ms
Atrium
Ventricle
Pulse Amplitude
maximum value
EN 455002-2-1
mean value
3.6 +0.1/-0.7
3.3 +0.1/-0.7
Pulse width
0.42 ± 0.02 ms
Sensitivity
15 ms sin2
40 ms sin2
0.2 + 0.05/-0.1 mV
2.5 ± 0.5 mV
EN 455002-2-1
delta pulse
0.24 + 0.05/-0.1 mV
2.5 ± 0.5 mV
Refractory period
425 +10/-20 ms
250 +10/-20 ms
200 +20/-5 min-1
Runaway protection
Product Line
Model
Lead Connection
Catalog Number
Cylos DR
uncoated
coated
IS-1
IS-1
349799
349804
Cylos DR-T
uncoated
coated
IS-1
IS-1
349806
349810
Cylos VR
uncoated
coated
IS-1
IS-1
341824
341815

162
Technical Data
Block Diagram for Cylos DR
Figure 28: Block Diagram for Cylos DR

163
Technical Data
Block Diagram for Cylos DR-T
Figure 29: Block diagram for Cylos DR-T

164
Technical Data
Block Diagram for Cylos VR
Runaway
protection
Figure 30: Block Diagram for Cylos VR

165
Technical Data
Federal Communications Commission
Disclosure
The CYLOS DR-T pacemaker is equipped with an RF transmitter for
wireless communications. This transmitter is authorized by rule under
the Medical Implant Communications Service (47 CFR Part 95) and
must not cause harmful interference to stations operating in the
400.150 - 406.000 MHz band in the Meteorological Aids (i.e.,
transmitters and receivers used to communicate weather data), the
Meteorological Satellite, or the Earth Exploration Satellite Services and
must accept interference that may be caused by such aids, including
interference that may cause undesired operation. This transmitter shall
be used only in accordance with the FCC Rules governing the Medical
Implant Communications Service. Analog and digital voice
communications are prohibited. Although this transmitter has been
approved by the Federal Communications Commission, there is no
guarantee that it will not receive interference or that any particular
transmission from this transmitter will be free from interference.
The FCC ID number for this device is: PG6CYLOS.

166
Technical Data
Terms and Abbreviations
AA
Interatrial conduction time
AESW
Atrial extrasystole interval (atrial extrasystole window)
ARP
Atrial refractory period
AUI
Atrial upper interval
AUR
Atrial upper rate
Autoshort
Capacitor discharge time after pace
AV
Interval between an atrial action and the following ventricular action
Blanking
BiA , BiV
Biatrial, biventricular
BI
Basic interval
BOS
Beginning of service (for the implant)
Cross-Triggering
After atrial sensing events, pacing occurs in the other atrium
Cut-off voltage
Minimum operational voltage of the implant
Detection
Evaluation of a sensed signal by the implant
DSS
Reduction interval (decrement step size)
Double-Triggering
In response to each atrial action, triggering follows in both atria
EMI
Interference that causes the pacemaker to switch to a safety mode
(electromagnetic interference)

167
Technical Data
EOS
End of pacemaker functioning (end of service)
ERI
Replacement indication (elective replacement indication)
FFP
Far-field protection
Home Monitoring
The implant data are made available to the treating physician via the
cellular phone network and the Internet
IAC
Interatrial conduction time
LA
Left atrium
LAESW
Left atrial extrasystole safety window
LV
Left ventricle
MAR
Maximum activity rate (= sensor rate)
MOR
Maximum overdrive rate
Mode
Mode, pacing mode
MSW
Mode Switching
Multisite
Pacing via the pacemaker's third channel
NIPS
Non-Invasive Programmed Stimulation. No additional devices are
needed for external pulse control, use only implants, programmers,
and software that are intended solely for this function.
OAR
Overdrive average rate
Overdrive
Overdrive pacing
pace
Paced event
PMT
PMT protection (pacemaker-mediated tachycardia)

168
Technical Data
RA
Right atrium
RAESW
Right atrial extrasystole safety window
Rate fading
Rate smoothing. If the rate suddenly drops, e.g., upon the onset of
bradycardia after a higher intrinsic rate.
RV
Right ventricle
Sense
Sensed event
SMS
Short messages via cellular phone (short message service)
SW
Safety interval (safety window)
Triggering
Forwarding and triggering of an action
ULAS
Left atrial sensing not used for timing the pacemaker (u = unused)
UTI/UTR
Upper rate limit (upper tracking rate/interval)
VES
Ventricular extrasystole (synonym: PVC = premature ventricular
contraction)
VES lock-in
By definition, an atrial event that occurs during the atrial refractory
period will not start a new basic interval.
VV
Interventricular conduction time

169

Technical Data
170
Index
Index
A/V rate trend......................................................... 98
A/V impedance trend ..........................................108
AAI mode ................................................................. 27
active capture control (ACC) .......................... 51-56
activity chart..........................................................107
AES classification.................................................101
AES coupling interval...........................................104
antitachycardia functions..................................8, 62
anti-theft installations..........................................135
AOO mode................................................................ 27
arrhythmia ranges................................................102
arrhythmia statistics............................................100
AV delay ................................................................... 39
dynamic.............................................................. 39
safety .................................................................. 44
AV hysteresis.......................................................9, 40
CLS...................................................................... 80
repetitive ............................................................ 41
scan..................................................................... 41
AV-sequential pacing ............................................. 23
basic rate................................................................. 33
battery....................................................................154
date......................................................... 112, 128
status................................................................123
blanking period, ventricular.................................. 43
block diagrams .....................................................158
BOS (beginning of service) .................................129
burst stimulation.......................................................9
capture control, active (ACC) ......................... 51-56
catalog numbers of products .............................157
cautionary notes...................................................132
cellular phones......................................................134
Closed Loop Stimulation....................................... 78
adapting parameters for ................................. 80
dynamic.............................................................. 80
feature, as a....................................................... 78
modes of ............................................................ 21
required VP......................................................... 80
self-calibration of.............................................. 79
safety feature..................................................... 81
complications........................................................132
contraindications.................................................... 11
contraction dynamics ............................................ 79
coupling interval
AES....................................................................104
VES....................................................................105
Cylos DR, service times for.................................131
Cylos VR, service times for ................................131

171
Index
DDD mode ............................................................... 22
DDI mode................................................................. 25
DDT/A mode ........................................................... 28
DDT/V mode ........................................................... 28
default programs..................................................150
defibrillation, and interaction with pacemaker136
detection functions.......................................... 48, 57
diathermy...............................................................137
disposal instructions............................................140
DOO mode ............................................................... 27
DVI mode................................................................. 26
elective replacement indication.........................129
electrical data .......................................................154
electrocautery .......................................................139
electromagnetic interference (EMI)....45, 133-135
EOS.........................................................................129
ERI.................................................................................. 129-131
event counters......................................................... 97
explantation...........................................................140
external pulse control..........................................114
factory settings
tolerances ........................................................156
follow-up, options for...........................................110
functions
AES classification ................................................9
antitachycardia .............................................8, 62
automatic........................................................... 10
automatic lead check..........................................9
AV hysteresis.................................................9, 40
lead check.......................................................... 50
memory ..........................................................9, 95
mode conversion........................................ 12, 65
mode switching......................................8, 12, 67
night program ...............................................9, 37
other .................................................................149
overview of................................................31, 149
overdrive pacing...................................................8
PMT............................................................... 70-73
rate hysteresis...............................................9, 33
sense compensation ........................................ 43
sensor....................................................................9
special ...................................................................8
timing ................................................................. 33
VES classification ................................................9
fusion beats and CLS............................................. 81

172
Index
handling .................................................................118
household appliances..........................................134
high-frequency diathermy...................................137
home monitoring, parameters for .....................141
hyperbaric oxygen therapy .................................139
hysteresis
AV hysteresis..................................................... 40
CLS and AV hysteresis..................................... 80
rate...................................................................... 33
ICDs and interaction with pacemakers.............136
IEGM, realtime transmission of .........................110
impedance, changes in.......................................... 79
impedance trend ..................................................108
implant data
electrical...........................................................153
mechanical ......................................................155
implantation..........................................................118
indications ............................................................... 11
interference, pacing during ..........................45 - 47
interruption of CLS................................................. 81
intrinsic AV conduction ......................................... 99
introduction................................................................7
IS-1 connector............................................. 121, 122
leads
check, automatic .............................................. 50
configuration ..................................................... 49
connecting ...............................................119-122
data......................................................... 112, 128
impedance monitoring........................................9
lithotripsy...............................................................138
magnet effect .................................................... 29-30
magnet response, after ARI or ERI....................130
magnetic resonance imaging (MRI) ..................138
malfunctions, technical.......................................132
markers..................................................................110
materials, used for pacemaker ..........................153
mechanical data ...................................................155
memory functions, diagnostic..........................9, 95
minimum PVARP.................................................... 64
mode conversion .......................................................8
mode switching................................................ 12, 67
trend .................................................................100
modes..............................................................21, 141
AAI............................................................................ 27
AOO..................................................................... 27
CLS...................................................................... 21
DDD..................................................................... 22
DDI...................................................................... 25
DDT/A................................................................. 28

173
Index
DDT/V................................................................. 28
demand .............................................................. 28
DOO..................................................................... 27
DVI............................................................................ 26
OFF...................................................................... 29
overdrive...................................................... 22, 73
overview of (table) ............................................ 31
triggered............................................................. 28
VDD..................................................................... 26
VDI............................................................................ 29
VOO..................................................................... 27
VVI............................................................................ 27
mode conversion .................................................... 12
automatic........................................................... 65
myopotentials .......................................................132
NBG code................................................................. 10
night program .....................................................9, 37
NIPS (non-invasive programmed stimulation) 114
non-programmable parameters/range of values141
OFF mode ................................................................ 29
overdrive mode ............................................8, 22, 73
overdrive pacing .................................................8, 22
overdrive pacing, preventive................................. 73
protective function of....................................... 75
levels of ............................................................. 74
P/R-wave test........................................................114
pacing, triggered .................................................... 28
pacing
functions ..................................................... 48, 57
modes .......................................................21, 141
statistics...........................................................108
pacing threshold, testing of ...............................124
packaging ..............................................................118
parameters
pulse .................................................................143
special ...................................................................8
timing ...............................................................143
patient data memory ...........................................117
physiological rate adaptation............................... 78
PMT management ........................................8, 70-73
detection of........................................................ 72
prevention of...................................................... 71
protection from ................................................. 72
refractory period extension............................. 71
termination of.................................................... 73
polarization artifacts.............................................. 52
procedures, risky therapeutic and diagnostic 135
product line ...........................................................157
programs, default settings..................................150
programmer ...................................................10, 153
programming wand, position indicator ............117

174
Index
pulse
amplitude........................................................... 48
control, external...................................................9
data......................................................... 112, 128
parameters ......................................................143
width ................................................................... 48
PVARP, minimum................................................... 64
P-wave trend..........................................................107
quality of CLS.......................................................... 81
radiation therapy..................................................137
rate
decrease............................................................. 86
fading.................................................................. 88
forecast ............................................................113
histograms......................................................... 98
increase.............................................................. 85
rate adaptation..............................................77, 147
accelerometer-based........................................ 77
adjusting ..........................................................126
Closed Loop Stimulation................................. 78
modes of ............................................................ 21
rate hysteresis.....................................................9, 33
repetitive ............................................................ 34
scan..................................................................... 35
rate trend..................................................... 106, 113
A/V ........................................................................... 98
replacement indication........................................129
parameters ......................................................147
refractory period..................................................... 38
required VP .............................................................. 80
retrograde conduction, testing for .......... 114, 125
R modes................................................................... 21
R-wave trend..........................................................107
safety, in the workplace.......................................135
safety feature of CLS.............................................. 81
safety margin .......................................................... 55
self-calibration of CLS ........................................... 79
sense compensation.............................................. 43
sensing function, testing of ................................125
sensing statistics..................................................107
sensitivity................................................................. 48
service times ............................................... 131, 154
sensor
features..................................................................9
histogram .........................................................106
simulation .......................................................... 87
statistics...........................................................106
threshold ............................................................ 84
threshold, adjusting .......................................127
trend........................................................ 106, 113
sensor gain...........................................................3,82

175
Index
automatic ..............................................................8
adjusting...........................................................127
sensor rate, maximum .......................................... 86
settings, factory, tolerances ...............................156
software, for programmer..................................... 10
statistics................................................................... 95
arrhythmia .......................................................100
interrogating...................................................... 96
pacing...............................................................108
timing ................................................................. 97
sensing .............................................................107
sensor...............................................................106
starting............................................................... 96
sterilization............................................................118
storage conditions...................................... 118, 155
tachyarrhythmia, paroxysmal atrial.................... 13
tachycardia mode................................................... 63
tachycardia behavior.............................................. 65
mode switching................................................. 67
mode conversion............................................... 65
technical data .......................................................141
telemetry, analog..................................................112
temporary program..............................................115
TENS.......................................................................137
TF T display .............................................................. 21
threshold search, automatic................................. 52
threshold test ........................................................113
timing .............................................................. 33 – 45
intervals....................................................... 24, 31
parameters ......................................................143
statistics............................................................. 97
triggered pacing ..................................................... 28
upper tracking rate ................................................ 62
vasovagal syncopes................................................ 36
VDD mode................................................................ 26
VDI mode................................................................. 29
ventricular blanking period................................... 43
ventricular evoked response (VER)...................... 51
ventricular extrasystoles (VES)
classification of.......................................... 9, 104
coupling interval .............................................105
VOO mode................................................................ 27
VVI mode.................................................................. 27
workplace safety...................................................135
X-ray identification...............................................155
x/z-out-of-8 algorithm ........................................... 67


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