MIE Medical Research TF5-RX HEART RATE VARIABILITY MONITER User Manual VariaCardio TF5

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Date Submitted	2003-06-24 00:00:00
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Document Title	VariaCardio TF5 User Manual
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Document Author:	AMDG

System for Telemetric, Non-invasive, Computer-aided
Evaluation of Heart Rate Variability
®
USER MANUAL
© 2001-2003, Advanced Medical Diagnostics Group, Ltd.
Doc 125-05
VariaCardio® TF5 Manual
Table of contents:
1.BEFORE YOU BEGIN
1.1 WARNINGS
DISCLAIMER OF WARRANTY
1.2. VARIACARDIO TF5 HELP LINE
1.3. CARING FOR THE VARIACARDIO TF5 SYSTEM
1.4. TECHNICAL AND SAFETY NOTES
2. GENERAL DESCRIPTION
2.1. PARTS OF THE VARIACARDIO TF5
2.1.1. CHEST BELT WITH UHF-TRANSMITTER
2.1.2. UHF-RECEIVER
2.2. OTHER COMPONENTS / PRINTER
2.3. AC/DC ADAPTER FOR A TRANSMITTER BATTERY AND GUIDELINES FOR ITS CHARGING
2.4. PRODUCTION, TESTING, WARRANTY AND TECHNICAL SUPPORT
10
12
13
14
14
3. VARIACARDIO TF5 PROGRAM PRINCIPLES & CONTROL
16
3.1. WHAT THE SWITCH BUTTONS MEAN
3.2. WHAT THE LED DIODES MEAN
3.3. WHAT IS THE NORMAL OPERATION SETTING
16
16
16
4. OPERATING THE VARIACARDIO TF5
17
4.1. HOW TO INSTALL THE SOFTWARE
INSTALLATION WIZARD
4.2. HOW TO LAUNCH THE APPLICATION
4.3. HOW TO ADJUST THE BELT
4.4. HOW TO ADJUST THE COMMUNICATION RECEIVER/COMPUTER:
4.5. HOW TO ENTER THE DATA AND/OR TO CONTROL THE SYSTEM
17
18
21
22
22
23
5. CLINICAL USE OF THE SYSTEM: DATABASE
24
5.1. BEFORE WE START
5.2. HOW TO START THE PROGRAM
5.3. THE BASIC OPERATION SCREEN
5.4. DATABASE: HOW TO FIND A SUBJECT
5.5. DATABASE: HOW TO ADD A NEW SUBJECT RECORD
5.6. DATABASE: HOW TO DELETE A RECORD / SUBJECT
5.7. DATABASE: HOW TO CHANGE THE DATABASE / CREATE A NEW DATABASE
24
24
25
27
27
29
29
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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5.8. DATABASE: HOW TO SET THE DATABASE AS DEFAULT
5.9. DATABASE: HOW TO IMPORT DATA OBTAINED BY PREVIOUS MODELS
5.10. DATABASE: HOW TO COMPACT THE DATABASE
5.11. LICENSE, HARDLOCK, DATA PROTECTION & BUSINESS ISSUES
5.12. HOW TO SEND RECORDS AND PROTOCOLS VIA E-MAIL
5.13. HOW TO EXPORT AND IMPORT HRV RECORDS
6. CLINICAL USE OF THE SYSTEM: MEASUREMENTS
6.1. MEASUREMENTS: SPECTRAL TEST MEASURING SCREEN
6.2. MEASUREMENTS: HOW TO PERFORM MEASUREMENT
6.3. HOW TO BROWSE/EDIT THE DATA
6.3.1. ECG BROWSER
30
30
30
31
31
32
33
33
34
38
41
7. CLINICAL USE OF THE SYSTEM: ANALYSIS
43
7.1. HRV BASICS. HOW TO UNDERSTAND THE PRINCIPLES OF ANALYSIS
7.2. HRV BASICS. HOW THE R-R INTERVALS MEASUREMENT WORKS
7.3. HRV BASICS. HOW TO UNDERSTAND THE 3D RESULTS
7.4. ANALYSIS. HOW TO PERFORM THE ANALYSIS
7.4.1. BASIC ANALYSIS SCREEN. 3D RUNNING SPECTRA GRAPH
7.4.2. BASIC ANALYSIS SCREEN. STATISTICAL TABLE
7.4.3. BASIC ANALYSIS SCREEN. GRAPHICAL TABLE
7.4.4. BASIC ANALYSIS SCREEN. RESUME
7.4.5. BASIC ANALYSIS SCREEN. EXPORT OF NUMERICAL RESULTS
7.5. ANALYSIS. MEDICAL REPORT AND HOW TO OBTAIN IT
43
45
46
48
48
50
50
51
51
52
8. BATTERY OF SHORT CARDIOVASCULAR REFLEX TESTS AS PROPOSED BY
EWING (SO-CALLED ‘EWING BATTERY’)
53
8.1. EWING BATTERY: INTRODUCTION
8.2. HOW TO PERFORM THE EWING’S TEST BATTERY
8.2.1. EWING BATTERY: HOW TO PERFORM THE DEEP BREATHING TEST
8.2.2. EWING BATTERY: HOW TO PERFORM THE VALSALVA MANEUVER
8.2.2. EWING BATTERY: HOW TO PERFORM THE ORTHOSTATIC TEST
9.1. SOME PRACTICAL EXAMPLES
9.2. APPLICATION NOTES
YOUR NOTES
53
53
55
57
58
60
61
63
The VariaCardio TF5 system is manufactured and distributed exclusively by Advanced Medical
Diagnostics Group, Ltd, UK and its partners.
© Copyright 2001-2003, Advanced Medical Diagnostics Group, Ltd. All rights reserved.
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
Doc 125-06
1.
Before You Begin
Thank you for purchasing this VariaCardio TF5 system.
The operating instructions that are found in this manual should be followed carefully to
ensure many years of reliable service. Please read these instructions thoroughly before using
the VariaCardio TF5 system.
The operating instructions should allow the average user to become familiar and proficient in
the review and editing of patient records generated by the VariaCardio TF5 system. This
manual does not teach the operator to recognise or to interpret the records. That
information is beyond the scope of this manual. An overview is described later in this
document.
Manufactured by:
MIE Medical Research, Ltd. for
Advanced Medical Diagnostics Group, Ltd.
6, Wortley Moor Road, Leeds, LS12 4JF
United Kingdom
Phone: +44 (0)113 279 1010
Fax: +44 (0)113 2310 820
Website: http://www.amdgmedical.com
E-Mail: TF5@amdgmedical.com
Your VariaCardio TF5 system Serial Number: _____________________
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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1.1 Warnings
•
•
•
•
•
•
Do not operate the VariaCardio TF5 system on a patient with a heart
pacemaker or any other telemetrically (UHF range) programmable/controllable
device.
If a patient connected to the VariaCardio TF5 system is to be defibrillated, the
leads must be removed from the patient before defibrillation.
There are no user serviceable parts.
FCC Part 15 requirement:- This device requires a shielded interface cable
(RS232) to ensure compliance.
The operating UHF frequency range of 869.7 MHz (914.5 MHz USA only) used
for wireless ECG/RR data transfer is considered for general industrial, scientific
and medical use (‘ISM band’). Therefore, it might casually be possible that
disturbance caused by another wireless device working on the same operating
frequency occurs. This situation means in no way any hazard for patient.
However, it might be necessary to use another operating frequency for your
VariaCardio TF5 to work correctly.
User changes or modifications not expressly approved by AMDG/MIE could
void the user’s authority to operate the VariaCardio TF5.
Exclusions:
• Do not store or operate the VariaCardio TF5 system in a sterile, wet, damp or
dusty environment.
• Do not use the system in areas with explosive and / or inflammable gases.
• Do not store or operate the system in direct sunlight
• Only use antennae provided with the VariaVardio TF5 system.
Regulatory:
• FDA: This instrument is a Class II, Type B Applied Part device.
• CE: This device is a class 2a device with a measuring function.
• Accuracy is ± 1ms R-R interval measurement (equivalent to ± 0.1%)
• Suitable for continuous use.
• Use only battery charger supplied.
• This Product complies with:
o Electromagnetic compatibility FCC CFR 47, parts 15.249 for
intentional radiators
o Electromagnetic compatibility FCC CFR47, parts 15.109 for
unintentional radiators
o Electrical safety EN 60601-1:1993
o Electromagnetic compatibility EN 60601-1-2:1993, EN 61000-32:1995, EN 61000-3-3:1995, ETSI EN 300 220-3 V.1.1.1. (200009), ETSI EN 301 489-3 V1.2.1 (2000-08)
• Use only AMDG/MIE approved accessories to maintain integrity.
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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Symbols:
Warning – read instructions before use
Date of manufacture – MM.YY
Type B Applied Part
TX FCC ID: HH4TF5-TX Transmitter Federal Communications Commission
Identification number
RX FCC ID: HH4TF5-RX Receiver Federal Communications Commission
Identification number
This device complies with part 15 of the FCC Rules, Operation is subject to the
following two conditions: (1) This device may not cause harmful interference, and (2)
This device must accept any interference received, including interference that may
cause undesired operation.
This product is CE certified with notified body 0120
230V~50Hz
Suitable for use on mains power supply of 220V to 240V.
110V~60Hz
Suitable for use on mains power supply of 100 to 120V 60Hz
12V
12V dc input for charging internal battery
NOTE: NO USER SERVICEABLE PARTS.
FOR SERVICE CONTACT
MIE Medical Research Ltd
6 Wortley Moor Road,
Leeds,
LS12 4JF.
United Kingdom.
Tel:
+44 113 2793 710
Fax:
+44 113 2310 820
e-mail service@mie-uk.com
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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DISCLAIMER OF WARRANTY
The VariaCardio TF5 is manufactured by MIE Medical Research Limited for Advanced
Medical Diagnostics Group Ltd (AMDG). AMDG warrants only that the product is free
from defects in the materials and workmanship under normal usage, for a period of
12 months after receipt, and any implied warranty is also limited to 12 months.
The warranty for the TF5 is based on following the instructions indicated in the
“instruction and technical manuals”. However in no event shall MIE Medical Research
Limited be liable for any damages whatsoever arising out deviation from these
instructions.
This manual provides information for the operation, set-up and care of the
VariaCardio TF5 system. The system does not require a trained technician to
determine fiducial points and/or pattern recognition to achieve its specific
performance. All analysis is performed automatically within the unit using the
parameters set at the beginning of the procedure. The physician or the operator may
perform editing of the obtained data immediately at the end of the recording session
or any time later.
1.2. VariaCardio TF5 Help Line
Advanced Medical Diagnostics Group provides a help line for all your technical and
other questions Mon-Fri between 9:00 AM and 5:00 PM of UK time:
Phone: +44 (0)113 279 1010
Fax: +44 (0)113 2310 820
Website: http://www.amdgmedical.com
http://www.mie-uk.com
E-Mail: TF5@amdgmedical.com
1.3. Caring for the VariaCardio TF5 System
Cleaning instructions:
The system may be cleaned with any non-corrosive disinfectant commonly used for
superficial skin disinfection purposes. Use a damp cloth to clean the instrument.
Do not expose the system to steam, corrosive liquids, high temperatures or any kind
of radiation/sterilisation. This equipment is not protected for the ingress of liquids.
Shipment/transportation and long-term storage:
The system has been thoroughly checked in standard transportation environments
e.g. air, road, rail & sea. There was no deterioration in its safety or function
recorded. The instrument should be stored in temperatures of between +5 and +35
°C and humidity up to 75%.
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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Inspection and service:
The manufacturer recommends the system to be thoroughly checked once every 2years. This check will be performed exclusively by the manufacturer or its local
authorised service centre. Please contact your distributor for more details.
Unauthorised servicing of this equipment voids any guarantees and the manufacturer
or distributor cannot accept any liability as to its proper functioning or safety.
Environmental information:
The system includes a Lithium ion battery, which is to be replaced exclusively by
authorised facility. If the system is to be inactive for long periods of time, please
contact your distributor to ensure all local environmental laws are met.
Technical information:
There are no serviceable parts inside. Exchange of internal battery will be provided
only by your authorised service centre. Please contact your distributor’s office.
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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1.4. Technical and Safety Notes
Safety:
The system must be connected only to computer complying to EN 60950. Use only
the connecting cables supplied with the system (<3m).
Installation requirements: The system must be installed at a minimum distance of
1.5 m from the patient, or the computer must be connected to a separating
transformer. Take care of possible hazards caused by the summation of leakage
currents when several electronic instruments are interconnected.
Use only the AC/DC adapter delivered with the system. Check if the voltage of the
power supply matches your local mains supply (110/220/240 V).
The chest belt with flat electrodes used in the VariaCardio TF5 is manufactured to
conform with the MDD 93/42/EEC (AUT76 1032-029-98). Additionally, during the 5years practical experience - no side-effects or bio-incompatibility effects related to
the use of this chest belt have been reported.
If the ECG amplifier is inoperable due to an overload or saturation, the yellow LED on
the transmitter stops blinking (according to EN 601-2-25, clause 6.8.2).
The VariaCardio TF5 complies with Medical Device Directive 93/42/EEC, including the
international standards of electrical safety and electromagnetic compatibility.
Physicians’ review:
The ability of trained people to recognise certain patterns can be better than
machines in certain circumstances. Therefore the user should be aware of the
fallibility of such equipment in performing these tasks. This caveat applies to the
various artefact/pattern recognition tasks performed by all ECG analysis systems
including the TF5 system. Therefore, no significant diagnostic/treatment decisions
should be made solely based on the results of the equipment’s analysis. In such
cases, users should satisfy themselves with the accuracy of the equipment’s analysis
by confirming it with the underlying heart beat/ECG data as contained in the
obtained records.
Recommended PC equipment:
For problem-free use of the VariaCardio TF5 system, you should use a dedicated IBM
PC-compatible computer with the following
(a) minimum specifications: CPU Pentium 200 MHz, 32 MB RAM and 10 MB of
available hard disk space (optionally, a notebook with identical features), 1
free serial port, with MS-Windows version 98, Second Edition and any
commonly used printer, or
(b) optimum specifications: CPU Pentium III 500 MHz and higher, 64 MB RAM and
20 MB of available hard disk space (optionally, a notebook with identical
features), 1 free serial port, with MS-Windows version 98, Second Edition
/2000, and laser (colour) printer.
Notice:
In accordance with an ongoing development and improvement of the technology, the
manufacturer reserves the right to change/adapt any procedure used in the system.
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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2.
General Description
VariaCardio TF5 is a telemetric, on-line, computer-aided system for the
examination of heart rate variability, based on its time-domain and
frequency-domain (spectral) analysis. The system can be used in any
clinical or research environment.
The system telemetrically collects and stores data derived from one-channel ECG
(both, intervals between consecutive normal R waves, and ECG signal separately)
obtained during a standardised modified orthostatic test (within positions
supine/standing/supine, each of them being 5 minutes long) or during a battery of
cardiovascular reflex tests. Such a test is performed under strictly standardised
conditions excluding any external disturbance. An option to evaluate the test is then
immediately available, this enables the user to get a quick, accurate, quantitative,
highly standardised and evidence-based information on the current state of a
examined subject that can be used in the further decision making process.
Analysis of heart rate variability has been accepted by the medical community to
assess cardiac autonomic function fully non-invasively, to explore the
pathophysiological mechanisms of heart diseases, to evaluate effects of therapy
and/or to predict long-term prognosis.
2.1. Parts of the VariaCardio TF5
Hardware:
(1) An adjustable chest belt with two flat electrodes and an on-board MCU-based
signal-analysis unit combined with built-in battery-powered UHF-transmitter,
(2) An UHF-receiver connected directly to an IBM-PC compatible computer via the
serial port via an RS-232 connection,
(3) AC/DC adapter, cables, accessories.
UHF-Receiver
Chest belt with
UHF-Transmitter
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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Software:
A data collection, digital encoding, transmission and analysis software package
enables the transmitted data to be displayed, stored and edited. The patient heart
rate variability data and ECG can be displayed online and analysed offline in different
graphical forms and can be printed out together with standardised statistical reports
on any commonly used printer.
The system offers the following examination features:
• A short-term spectral analysis of the heart rate variability using a Fast Fourier
Transform permitting a quantification of the influence that individual components
of the autonomic nervous system have on the heart rate. The variability is
evaluated by following indices: (a) in “frequency domain” - absolute and relative
spectral power in two or three frequency bands, their ratios, total and cumulative
total power, power spectral density, average frequency, (b) in “time domain” averaged R-R interval, its standard deviation and MSSD, usually in 3 examination
intervals (of 300 seconds each). The system offers the possibility to monitor the
instantaneous heart rate (time resolution 1 ms) and spectral curve in real time on
the computer monitor.
• Commonly used ‘gold-standard’ Ewing’s battery of cardiovascular autonomic
function reflex tests, including a registration of changes in the heart rate during
relaxed and deep breathing, Valsalva maneuver and orthostatic load. System
enables an immediate statistical evaluation of all commonly used indices and
offers a possibility to store, print and/or process patient data.
• Single channel ECG with a time resolution of 2 ms, with a possibility to
continuously monitor, store, print and/or process patient data.
It is possible -- due to the UHF-radio telemetric data transfer -- to perform the
examination from a distance of 20-30 metres or longer, e.g., in a separate
examination room.
2.1.1. Chest Belt with UHF-Transmitter
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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10
a) Overview - The UHF-transmitter consists of an adjustable chest belt with two
integrated flat rubber electrodes. The single channel ECG and R-R interval is sent
to an on-board signal-conditioning unit incorporating a central processing unit
microchip. The data is analysed prior to transmission. The ECG signals are
sampled at 500 Hz whereas the R-R intervals are sampled at 1000 Hz. Another
data channel is used for checking the transmitter battery voltage level.
b) Front panel – The front panel has two Light Emitting Diodes (LED’s). The yellow
one indicates that data transfer is functioning. The green one is used for indicating
the charging procedure. A miniature power switch switches the telemetric unit on
and off.
c) Bottom panel - contains an input socket for connecting the AC/DC adapter cable
(for the transmitter battery charging).
AC/DC adapter
input socket for connecting
the AC/DC adapter cable
Technical data:
•
•
•
•
•
•
•
•
Data acquisition:
Two flat rubber electrodes
sampling rate for ECG signal
sampling rate for R-R intervals
500 Hz
1000 Hz
Transmission:
output power
10 mW
operating frequency range
869.7 MHz (914.5 MHz USA
only) (ISM Band; for local radio frequency approval check the
Technical files or contact your distributor)
supply voltage (integral rechargeable Li-Ion battery) 3.7 V DC
operating time (continual transmission)
more than 10 hours
dimensions (LxBxH)
80x40x30 mm
weight including battery (without chest belt)
160 g
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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11
2.1.2. UHF-Receiver
a) Overview - The UHF-receiver is housed in a metal case with two BNC connectors
for the antennae on the top. The received data is transferred via the RS232 port
to a computer.
b) Front panel - Contains two LED-diodes (yellow one signalling power is ON, green
one for checking of functional data transfer)
c) Back panel - Contains one outlet connector CANON for the connection cable into
the computer (via COM1 or COM2 port) and one connector for the AC/DC adapter.
A power switch switches the receiver ON and OFF.
Technical data:
•
operating frequency range
•
•
•
•
•
•
sensitivity
antennae
communication protocol
supply voltage
dimensions (LxBxH)
weight
869.7 MHz (914.5MHz USA
only ISM Band)
0.3 µV
lambda/4 type
RS 232 (IBM-PC)
9-12 V
170x115x30mm
390 g
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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12
Back panel of UHF-receiver
connector for
AC/DC adapter
power switch switches
the receiver ON and OFF.
outlet connector for connection
cable into computer
AC/DC adapter: (complies with IEC 60-601).
Important notice:
• Testing of functionality is only possible when the whole system is in
operation, i.e., the transmitter broadcasts regular signals -- the yellow LED diode
is regularly blinking according to the current patient’s heart rate, the receiver is on
/yellow diode/ and receives data /green diode/, and it is connected to a computer
on which the respective program is running.
2.2. Other Components / Printer
By arrangement, the systems can be delivered with an IBM-PC compatible computer
and monitor. Minimum operation system requirement is a MS-Windows version 98 or
higher.
When installing the program on to a PC, it is highly recommended to dedicate this
computer only to measurements of the autonomic nervous system. If the system is
installed on a computer that is used for another purposes, there is a risk that
software conflict may occur. In this case the manufacturer of VariaCardio TF5 cannot
be held responsible for any damage incurred to the system and its use.
The system runs with any standard (commonly available) printer. For better
documentation results it is recommended to use an ink-jet or a laser printer. For
professional presentations it is highly recommended to use a colour printer (inkjet/laser). After software installation check the appropriate printer installation (see
Chapter Options/Adjustment).
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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13
2.3. AC/DC Adapter for a Transmitter Battery and Guidelines
for its Charging
The transmitter contains a battery (3.7V Li-Ion), which provides a minimum of 24
hours continuous operation. For charging, use exclusively the AC/DC adapter
supplied.
Charging:
• Plug in the AC/DC adapter’s connecting cable into the input socket located in the
bottom panel of the transmitter.
• Plug in the mains cable of AC/DC adapter into the mains supply: the control
green diode on the adapter turns ON and the charging LED-diode on transmitter
also turns to green. After the battery is fully charged, the green diode turns off
and another LED-diode on the front panel of the transmitter turns to yellow.
• The charging process is controlled by electronics in the transmitter; there is no
risk of damage to the battery.
IMPORTANT NOTICE: While charging, the transmitter must
not be used on a patient!
2.4. Production, Testing, Warranty and Technical Support
The electronic components in the transmitter use surface mount technology. Prior to
final assembly, the circuits are checked and the whole system undergoes an 8-day
uninterrupted burn-in test with all functions tested.
Warranty:
Advanced Medical Diagnostics Group (AMDG) guarantees the VariaCardio TF5 when
new, to be free of defects in material and workmanship and to perform according to
the manufacturer’s specifications for a period of one year from the date of purchase
from AMDG or its authorised distributors or agents. AMDG will replace any
components found to be defective or at variance from manufacturer’s specifications
within this time. It shall be the purchaser’s responsibility to return the instrument
directly to AMDG or its agents, post-paid.
This warranty does not include cables, batteries and other accessories that are not
products of AMDG. This warranty does not include breakage or failure due to
tampering, misuse, neglect, accidents, modification, or shipping. This warranty is
void if the system is not used in accordance with the manufacturer’s
recommendations. This warranty is void if unauthorised or unqualified persons
attempt to make repairs. The warranty entitles the owner of the equipment to
replacement of the part(s) or unit at AMDG’s discretion. Purchase date determines
warranty requirements. In the case of a defect or other warranty service, please call
the authorised distributor AMDG for a Return Material Authorisation Form and return
the unit post-paid directly.
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14
The software is not guaranteed to function in every application or with non-standard
hardware and software. The warranty does not extend to damage to equipment
resulting from alteration, misuse, negligence, abuse, accident, unauthorised service,
vandalism or acts of God. A yearly check-up in AMDG or its authorised centres is
recommended; check of the system once in 2-years period is requested. Please
contact an AMDG representative for more details.
Technical support:
Is provided Monday to Friday (9am – 5pm UK time). Repairs are normally made
within 72 h (excluding shipping and other relevant operations), by replacing the
defective part/or the whole device, during the warranty period free. After the
warranty period, repairs will be billed according to the current company pricing
policy. The above mentioned technical support is exclusively provided by AMDG or its
authorised partners.
Helpline:
Advanced Medical Diagnostics Group provides a help line for all your technical and
other questions Mon-Fri between 9:00 AM and 5:00 PM of UK time:
Phone:
Fax:
Website:
E-Mail:
+44 (0)113 279 1010
+44 (0)113 2310 820
http://www.amdgmedical.com
http://www.mie-uk.com
TF5@amdgmedical.com
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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15
3.
VariaCardio TF5 Program Principles & Control
The VariaCardio TF5 (a) hardware is operated by using the power switch buttons
located on the transmitter and receiver and (b) software by program commands,
see below. Switch each button slowly and firmly, then release and check the
corresponding LED diode is on/off.
3.1. What the Switch Buttons Mean
(1) On transmitter: Turns the transmitter on and off (please be sure that the
transmitter is switched off after the examination)
(2) On receiver: Turns the receiver on and off
3.2. What the LED Diodes Mean
(1) Yellow LED diode on transmitter. After switching on, the transmitter informs
on occurrence of every detected R wave (heart beat) by short blinking of yellow
LED diode. Usually, the diode blinks in regular intervals around 1 second.
If an artifact / ectopic beat is detected, irregular blinking occurs. Typically, this
might happen when changing the examination position. In an extremely rare
case, a quick irregular blinking might mean a severe cardiac arrhythmia.
Therefore, in such cases immediately check the ECG signal and provide
appropriate diagnostic/therapeutic steps.
Green LED diode on transmitter is activated when the battery in the
transmitter is charged. When the charging process is finished, the green LED
diode turns off and the yellow LED diode constantly lights instead.
It is acceptable to leave the AC/DC adapter connected to the transmitter after the
charging is finished as the electronics within the transmitter prevents any
overcharging automatically.
(2) Yellow LED diode on receiver shows the receiver is on.
Green LED diode on receiver displays transmission/reception of data.
3.3. What is the Normal Operation Setting
•
Chest belt is positioned on the patient (for details, see the How to adjust the
belt chapter) and UHF-transmitter is switched on.
• UHF-receiver is switched on, antenna is mounted on the top.
• There is a connection cable between back panel of UHF-receiver and
COM1/COM2 port on the back of PC.
• AC/DC adapter is plugged-in, adapter cable is plugged into the back of UHFreceiver.
• Heart rate variability program runs on a dedicated computer with appropriate
operation system.
During the normal operation the system shows regular short blinking of yellow LEDdiode on transmitter with green and yellow LED diodes on receiver constantly being
(c) 2001-2003 Advanced Medical Diagnostics Group, Ltd
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16
on, while on the PC screen one-channel ECG signal with corresponding R-R intervals
and on-line spectral curve are being constantly refreshed.
4.
Operating the VariaCardio TF5
4.1. How to Install the Software
Note: Your VariaCardio TF5 system is usually installed & configured by an
experienced manufacturer’s technician or by one of authorised distributors so that it
is ready for use. In this case you can skip this section and proceed directly to next
Chapter 4.2. How to launch the application.
Important note:
It is strongly recommended that a dedicated computer be used for measurements of
the autonomic nervous system as a conflict with other software installations may
occur. In this case the manufacturer cannot be held responsible for any possible
problems.
Installation details:
The VariaCardio TF5 software must be installed onto your PC before it can be used.
Launching the installation wizard from our CD-Browser is extremely straightforward.
Note: To avoid any potential conflicts during installation, before launching the
installation wizard, it is recommended that you close any applications you are
working in. It is also good practice to make a complete backup of your system and
your critical documents/data/files to guard against any possible damage/loss.
1. Insert the supplied CD-ROM into the CD-ROM drive of your computer.
Within a few moments you should
be presented with the CD-Browser
pictured opposite.
Should the CD-Browser fail to
launch automatically it is possible
the ‘AutoPlay’ facility has been
disabled on your computer. In this
case you must launch the CDBrowser manually:
Browse the CD contents by doubleclicking on the ‘My Computer’ icon of
your desktop followed by your CDROM icon. Then locate and doubleclick on the file ‘Menu.exe’ (may
simply be displayed as ‘Menu’).
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2. Clicking ‘Install Products’ will display a list of programs supplied on the CD for
installation:
To begin the installation
process, click ‘VariaCardio
TF5’,
launching
the
Installation Wizard. Refer to
the Installation Wizard section
of this manual for details on
the installation process.
Once the installation process
is complete you must click
‘Menu’ to return the opening
page. Here you may choose to
review our website or register
the software.
3.
Finally, click ‘Exit’ to close the CD-Browser.
Installation Wizard
The VariaCardio TF5 software must be installed onto your PC before it can be used. Once
installed you may use the software without needing the CD-ROM. You must ensure your PC
meets the minimum requirements and provides the necessary ports (see the ‘Requirements’
section for more information).
The installation wizard is supplied on your CD-ROM and may be launched from the CDBrowser. Alternatively, updates may be downloaded via the internet or emailed from our
support team; these are simply launched directly from where you saved them.
Note: To avoid any potential conflicts during installation, before launching the installation
wizard, it is recommended that you close any applications you are working in. It is also good
practice to make a complete backup of your system and your critical documents/data/files to
guard against any possible damage/loss.
Having launched the installation wizard, proceed as follows:
1. After
some
internal
preparation, the installation
wizard welcomes you and
confirms the application to be
installed.
Click
‘Next’
to
proceed with the installation.
•
Important: On some systems,
the Microsoft Installer may need
to
update
critical
system
components
before
the
installation wizard can proceed.
You may be prompted to restart
your computer, after which the
installation
wizard
will
automatically resume and proceed
as normal. In extreme cases
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multiple restarts may be required.
2. You will be presented with the
end-user license agreement
which
you
should
read
carefully. Use the scrollbar and
arrows at the right hand side
to scroll down the document.
In order to use our software
you must accept the terms in
this agreement. Click the
button noting your acceptance
(‘I accept...’), then click ‘Next’.
3. Please complete the fields
prompting for your customer
information for registration.
4. You may select which users the
application is made available to
(useful
for
corporate
or
institution users). Selecting
‘Only for me’ avoids the
software being placed in other
users’ start menus, but does
not prevent them manually
launching the software directly.
If you are uncertain, you
should accept the default
selection. Note: ‘All users’ may
require you to be logged in with administration privileges (consult your administrator).
5. Once you are happy with the information entered, click ‘Next’ to proceed.
6. You may choose where the
application should be installed:
Should you wish to install to a
location other than the default,
click ‘Change’ to select an
alternative location.
Note: If installing for ‘All Users’ you
must select a location available to
every user bearing in mind their
privileges.
Once you are happy with the
install location, click ‘Next’ to
proceed.
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7. You may select the type of installation to be performed, then click ‘Next’ to proceed.
Complete installation installs the full
application with all features, help,
manuals & tutorials.
Custom installation allows you to
select exactly which features are to
be installed and the individual
install location of each component.
Note: Custom installation is only
recommended for advanced users and
is not documented here.
8. The wizard has ascertained all
the necessary details to begin
installation. This is your final
chance to review the summary
of the options you have
selected.
Click ‘Install’ to begin the
physical installation process.
Alternatively, if you would like to
review/change any of the
options use the ‘Back’ button to
backtrack through the selection
process.
9. The features you selected will
now be installed. Please wait
while the process completes.
This
task
may
several
moments.
Once complete, the wizard will
inform you as to the success of the
operation.
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10. Typically you can click ‘Finish’
to exit the installation wizard.
Note, however, if some files in
need of updating were in use,
you may be prompted to
restart your computer. These
files will then be updated
during the restart and the
wizard will exit automatically.
The checkboxes allow you to launch
the application upon exiting the
wizard and give you the opportunity
to review the release notes which
outline any last minute addendums
to the manual and provide
information
on
any
fixes,
enhancements or known problems with the release.
4.2. How to Launch the Application
Once installed, the VariaCardio TF5 software can be launched from your desktop or start
menu.
From your desktop:
1. Locate and double-click on the
‘VariaCardio TF5’ program icon on
your desktop (here highlighted in
yellow).
N.B. Depending on your settings, it
may only be necessary to singleclick the icon in order to launch the
application.
Alternatively, from the start menu:
1.
Click on the ‘Start’ button.
2.
Click on the ‘Programs’ folder from the list.
3. Click on the ‘AMDG’ folder.
N.B. Depending on your settings, this entry may
appear at the foot of your list rather than in
alphabetical order.
4.
Click on the ‘VariaCardio TF5’ folder.
5.
Click on the ‘VariaCardio TF5’ program icon.
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4.3. How to Adjust the Belt
It is important to adjust the belt on the patient’s chest so that the transmitter is
located exactly in the middle of the thorax. If the original signal is not obtained
correctly, the LED diode on the transmitter blinks irregularly or not at all. If this
happens (assuming that there is NO cardiac arrhythmia), the reason could be that
the electrical heart axis is shifted. In this case, it is recommended to shift the whole
transmitter belt to the left so that a signal is regularly transmitted again. Rarely, in
some cases, it may be necessary to turn the whole thorax belt upside-down so that
the red electrode is on the right side. You can check the general quality of the signal
on the monitor in the option/display “Hardware info” in the basic screen. Usually, an
optimal ECG signal should have a high, dominant, positive R-wave.
! Summary:
1. Adjust the chest belt on the patient’s chest (as described above, see the
photo)
2. Switch the power on the transmitter
3. Check the regularity of the yellow LED-diode signal on the transmitter and
adjust the position of chest belt if necessary
4. Switch the power on the receiver
5. Start the program and check the ECG/heart rate display on the monitor in
the “Hardware info” option. Afterwards, start measuring.
4.4. How to Adjust the Communication Receiver/Computer:
The most commonly used communication port is COM1. The default is set to COM1.
The program automatically checks for available communication ports and shows
them in the “Engineering” option, should you wish to manually adjust.
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Adapter to
mains supply
Cable
to PC,
COM
port
4.5. How to Enter the Data and/or to Control the System
" Using the keyboard: simply press the key with number or letter as indicated,
or use the arrow /Tab keys to change the position on the screen and press
ENTER afterwards.
# with
Using the PC mouse makes some tasks easier: where available, simply click
the left mouse button on the symbols/icons on the screen as displayed.
While browsing the heart rate record, simply click on an appropriate heartbeat
in order to mark or select it.
“CTRL” + “KEY”
Using the ‘hot keys' enables by pressing a certain combination of two keys
(mostly CTRL or ALT + letter/number, see the underlined letters in various
program menu options) to activate a certain procedure. Where possible, for
experienced users this allows more fluent program operation while avoiding
time-consuming positioning of mouse on the PC screen or using arrow keys.
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5. Clinical Use of the System: Database
5.1. Before We Start
Generally, within the program, you can
move using the standard keyboard keys
$, %, PgUp, PgDn, Home and End, or
using the left button of the mouse (by
clicking directly on selected record or by
clicking on icons on the screen).
Also other standard Windows icons and
commands work as usual, like icons for
manipulation with active window (e.g.,
close, minimize, restore window) etc.
Important program steps
are
‘guarded’
by
alerts/warnings. These
short hints help the user
to
prevent
mistakes
and/or errors in data
handling like e.g., cancelling the data recording too early, omitting data saving,
exiting the program inappropriately etc.
5.2. How to Start the Program
Double click on the “TF5” icon on the
desktop. A “Welcome window” appears
and you are prompted to enter the
password that protects the program and
data against unauthorised use (if function
activated in ‘Engineering’ menu).
After entering the password, click on
“Logon” button; that is followed by the
message “Loading Database, Please wait” (this might take several seconds
accordingly to the size of database). Finally, a basic operation screen appears. The
usual way to get started with the program is to create or select an existing subject
record in the Database. In this program option, you can add, search, read, change
or delete any information relevant (for further information see next chapter).
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5.3. The Basic Operation Screen
(1)
The first line displays main program options – Database processing, HRV
Measuring, Browsing and Analysis sections, Engineering/program adjustments
and Help files. Using hot keys “ALT” + appropriate letter (as underlined) or
clicking on the option allows you to activate the submenu. You can also use
the program icons, see
description below.
(2)
The second part below this menu includes program icons that generally
correspond with the main program menu in the first line. Whilst the basic
screen shows the database of subjects, some additional icons/options for
database handling can be found in this menu (Database change, Setting
database as default, Deletion of current/selected record and Deletion of
current/selected subject). Further, all icons for data processing (Data recording, Data browsing and HRV analysis/3D Display) are located there, as well.
Database
change
Set this
database
as default
(3)
Delete
selected
record
Delete
selected
subject incl.
all records (!)
Start measuring phase
(reflex tests)
Browse
ECG
Perform HRV
analysis and
show 3D display
Browse R-R data or
Start measuring phareflex test results
se (spectral
analysis)
Most of the screen is covered by Database
of subjects and their records:
Program option “Display Subjects” allows the display of all subjects found in
a selected database, these may be sorted into order by clicking on/highlighting
the relevant item column. Each database subject record consists of
(a) personal data/items (see above – ID, Surname and first name, Date of
birth, Gender, Social insurance No, Address and three user-adjustable free
text fields) and
(b) test data - heart rate variability and/or one-channel ECG record (see
below). Record details relating to the selected subject are shown in a
separate window below the main database window.
In accordance with used test category, it is possible to process spectral analysis
/frequency-domain/ -- as obtained during modified orthostatic load -- or a battery of
short cardiovascular reflex /time-domain/ tests (so called Ewing battery, named
after its author, DJ Ewing). To choose one, just click on the test type option -“Spectral Test” or “Ewing’s Test”.
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In the “Spectral test” option, you can find/enter further record details:
Subject’s ID and
time point of
selected record
Comments /
Notes
Number
of RR
intervals
recorded
No of
markers/
initiations
of meas.
interval
No of
short 6sec. ECG
strips
recorded
(autom.artefacts)
No of
long 30sec. ECG
strips
recorded
(manual)
Whole ECG
record
length
(continuously; min)
In the “Ewing’s test” option, following record details can be found/entered:
Subject’s ID and
time
point
of
selected record
Comments /
Notes
Ewing test type:
DB – deep breathing
VM – Valsalva maneuver
OT – orthostatic test
Optionally: Blood
pressure systolic /
diastolic values
(e.g., value “1” initial,
value “2” final)
Practical example: The following screen shows an example of reflex
tests (Ewing’s) battery recorded in subject Test J (for subject’s details
see the upper panel of the screen with a small black arrow at the lefthand side), dated Jan 24th and 28th 2002: all Ewing’s tests of this
subject are listed in the lower part of the screen.
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5.4. Database: How to Find a Subject
By entering the first digits of ID or surname letters into the field “Find” located just
above the Database headings it is possible to find quickly the requested subject. The
corresponding subject’s personal record is indicated by a small black arrow on the
left-hand side in the Database window. Below the Database window, in the Records
section, the subject’s first recorded HRV data is marked, as well. In further data
processing, it is possible to browse personal data, HRV data or to analyse and display
the HRV data of selected subject’s record.
5.5. Database: How to Add a New Subject Record
•
Click on New Subject sheet: a single screen with personal data of the
selected subject is displayed, see above. Here it is possible to enter data of a
new subject. On completion, various standard fields (see above) can be
entered while the ID No, Surname, Date of birth and Gender are requested
items. ID checker prevents entering
identical ID or omitting to enter the
ID at all. Date of birth can be
selected in a calendar that becomes
available by clicking on the arrow in
this field, or it can be entered in
format dd / mm / yyyy. Gender
options can be selected by clicking
the arrow in the Gender field, as
well. When finished, click on Add
button to store the data.
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•
Edit option:
Allows you to edit the already entered data. Click on Edit button
opens access to all information with exception of ID. When finished, the new
information on subject can be Canceled or Updated using the corresponding
buttons.
By clicking the Data button at the
right-hand side, you can open an
auxiliary data window where free text
information can be entered. Three Aux
data windows are provided for each
subject. In the main program menu
Engineering-> submenu Program
Setup-> option Aux Caption it is
possible to adjust titles/headings
of these auxiliary data windows.
Bear in mind, please, that the
newly added / edited subject’s
data must be always saved =
“updated” before any further
processing is done: use the
Update button on the screen. If
you want to cancel the editing,
simply by pressing the Cancel
button.
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5.6. Database: How to Delete a Record / Subject
Mark subject’s record to be deleted by clicking on the
record with left mouse button. A small arrow at the lefthand side of database records listing appears. This
arrow identifies the record to be deleted by
•
•
•
Clicking on Delete Record icon
or
Selecting in main program menu: Database ->
Delete Record or
Pressing CTRL + R keys together.
Similarly, the database subject can be deleted
completely -- including all records -by
• Clicking on Delete Subject icon
or
• Selecting in main program menu: Database -> Delete Subject or
• Pressing CTRL + U keys together.
In both cases, a security alert appears in order to guard such (sometimes
unintended) action – see below. Just confirm, please, your decision.
5.7. Database: How to Change the Database / Create a New
Database
•
•
Click on Change Database icon
or
Open the Database menu, here
click on ->
Change or
• Press CTRL + N keys together
Then -- in the Open database window – either enter the
file name of the database to get opened or highlight it in
a listing and click on Open command.
Similarly, if creating a new database, enter simply the
name for the new database and click Open command.
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5.8. Database: How to Set the Database as Default
• Click on Set as default database
icon
or
• Open the Database menu, click on -> Set as default option or
• Press CTRL + D keys together
During starting procedure, program will automatically call this default database.
5.9. Database: How to Import Data Obtained by Previous
Models
It is possible to import data obtained by previous generations of VariaPulse® TF3 and
VariaCardio® TF4 systems so that you can individually compare progress of findings
over years. To do this, open Engineering submenu in the Main program menu.
Here, highlight the last option Load old data from directory. Alternatively, press
CTRL + L.
Then, in the “Varia load” window select the
subdirectory and/or files to be downloaded and
press Read button. Progress in data downloading
is shown graphically. When finished, close the
window. Newly downloaded
files are displayed in the
currently selected database. Be
aware, please, that older files
obtained by TF3 and TF4
systems
are
formatted
differently from the present database. It might be necessary to edit the subject
personal data (surname, date of birth etc.) before the downloaded files can be
processed.
5.10. Database: How to Compact the Database
From time to time it is useful to compact the database so that the data access is
quicker and database size gets smaller. To do this, click on Engineering and select
Compact database option (or press CTRL + O keys, see the figure above). The
process can take several minutes if the database is big, so please be patient.
We strongly suggest you to store a database copy separately from your computer.
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5.11. License, Hardlock, Data Protection & Business Issues
In order to maximally protect your sensitive data and the know-how of the system, a
special programmable, hi-tech hardlock is to be connected when using the system
VariaCardio TF5. This hardlock is connected with the PC via standard printer port
that can be found on the back of the computer. A “free” version of the TF5 program
– that does not require use of the hardlock -allows browsing the pre-recorded demo data and
its 3-D display & analysis only. All other practical
steps in clinical use of TF5 require connection with
the hardlock that includes license data specially
pre-programmed for the individual user in order to
allow her/him to make a maximum use of the
system in accordance with her/his business model.
Some relevant user-specific data (see below) are
downloadable from the connected hardlock in the
main menu section Engineering & License.
Important notice: Bear in mind, please, that programming the hardlock as well as
adjustment of your TF5 system license conditions require – at least initially -presence of AMDG or its authorised representative. Therefore, we strongly
suggest you to consult any step regarding such license manipulations in advance.
Otherwise, AMDG or its partners can not be held responsible for any direct in indirect
damage potentially occurring in this respect.
5.12. How to Send Records and Protocols via E-mail
Separate HRV records and/or complete examination protocols with comments can be
sent in encrypted form in order to enable consulting the data with the Remote
Analysis Centre and/or to facilitate delivery of the complete examination protocols to
related subjects. To do this, it is necessary first to adjust the e-mail addresses for
data exchange in the Engineering -> Program Setup -> Export/Send option:
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Then, select/mark the record to be sent - simply by
moving the arrow at the left/hand side of the basic
database screen (name of the subject in the upper
part of the screen, individual record/s in the lower
part). Afterwards, selected HRV data can be sent via a
standard e-mail program (MS Outlook) by choosing
option Database -> Send Record. Whenever
connected to Internet, the data will be automatically
sent to the address indicated in the Setup.
5.13. How to Export and Import HRV Records
Using Database->Export Record or Import Record option it is possible to
manipulate the selected record of chosen subject. This is typically done e.g. when
the HRV record is to be further processed separately (export) or a record from a
different database is to be imported into another one (import). The newly generated
file can be found in the
export directory as adjusted
in the Engineering ->
Program
Setup
->
Export/Send option.
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6. Clinical Use of the System: Measurements
6.1. Measurements: Spectral Test Measuring Screen
In the basic operation screen, click on icon Measuring
(or press CTRL + S or open
Measuring option in the main program menu and select ‘Spectral test’).
New screen Spectral test measuring is displayed with following main sessions:
(1) Commands
menu
including
submenu items Control, Save,
Browse, Window and Exit.
(2) Icons menu corresponding with the
above, including additionally Start
5&6
and Stop, Interval marking, Record
ECG icons etc., for details see below.
(3) Subject identification with ID,
Surname and Date of birth items.
(4) Hardware info shows the current
quality of data transfer/ECG in left
window and progress of heart rate
over recent time in the right window.
10
(5) Radio signal quality indicator, and
Battery status show current state of
these items.
11
(6) Alert window below the radio
signal and battery status indicators informs you of system configuration and of possible
errors (e.g., alert ‘Receiver switched off...’). A strip with information “OK” shows normal
setting, strip blinking in orange warns of errors and possible cause of the problem
encountered is displayed. Furthermore, pre-defined user’s limits – in accordance with
pre-set/prepaid service – and currently available number of TF5 test actions are shown.
(7) Record ECG section contains data on ECG record length from pressing the CTRL + E
hot keys or clicking on ECG record icon or pressing Record button, and information on
total number of ECG records in this measuring session. The default setting ‘–10 / +20’
shows that from the event the previous 10 seconds and following 20 seconds are
recorded (=30 seconds for each ECG record). The red button in this section shows ECG
strip recording.
(8) Artefact record section displays the number of artefacts and automatic artefact
recognition state. The button when green indicates normal heart rate data, when red
informs of automatically recognised and corrected artefacts (cardiac arrhythmia,
movement artefacts e.g., while changing position from supine to standing).
(9) Basic values window delivers exact numeric information on instantaneous R-R data:
Pulse number, Length of R-R interval in [ms], Heart rate in [beats per minute] and Time
elapsed since pressing Start button in [hrs:min:sec] (Note, please, that this total time
differs from the “Time remaining” information in the section 10).
(10) Statistic interval section is only active during recording the data for HRV analysis.
Once Mark button is pressed, analysis interval count number is shown (normally 1 – 3,
corresponding with examination procedure in 1-supine/2-standing/3-supine). Paralelly,
countdown for Time and number of Pulses remaining starts from 300 downwards.
(11) Measuring control buttons at the bottom of the window control program functions
such as Start, Stop, Save, Browse (R-R data) and (Browse) ECG.
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6.2. Measurements: How to Perform Measurement
6.2.1. Measurements: What to Do Before the Examination
Examined subject:
It should be noted that autonomic nervous system response depends on numerous
factors that influence the result of the examination:
• It is recommended to refrain from smoking or drinking coffee, tea, alcohol and/or
other sympathomimetic substances for 8-12 hours prior to examination.
• In patients with chronic medication, it is recommended to continue with their
usual medication and nutrition, with the exception of those using beta-blockers,
which have been shown to substantially increase the vagal tone (diagnostic
purposes!). In such case, consider an interim exchange with other
pharmaceuticals.
• Subjects with insulin treated diabetes should avoid hypoglycaemia within the last
12 hours.
Medical personnel:
Be sure that examination conditions meet the standards necessary to obtain reliable
and reproducible data:
• The examination should be performed in a quiet, gently illuminated room of a
constant temperature and optimally between 8:00 AM and 2:00 PM.
• Patients should be requested to lie down quietly for a preparatory phase of 10-15
min to exclude relevant emotional or external influences on the autonomic
regulation.
• In general, during the examination, speaking or physical activities that are not
related to the testing procedure should be avoided.
• It is recommended not to make any telephone calls or undertake any other
activities that may influence the steady state of autonomic regulations during the
examination period.
• Ideally the examiner instructs the subject on the measurement procedure, enters
personal and other relevant data and leaves the examination room leaving the
examined subject alone.
• Check there is no conflict with the chapter 1.1. Cautionary Information in the
Manual.
6.2.2.Measurements: What to Do During the Examination
(a)
Start the program, Select / Add the new
subject in Database
(b)
Adjust the chest belt and switch the
transmitter on.
(c)
Check if the yellow LED diode on
transmitter is regularly blinking. Switch
on the receiver and check if its both LED diodes are on.
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(d)
Click on Spectrum Measuring section icon
(or press CTRL + P or
open Measuring option in the main program menu and select Spectrum).
(e)
Spectral test measuring screen is displayed. Hardware info section
(object No 4, see chapter 6.1. Spectral test measuring screen) is activated
immediately. Check quality of transmitted & displayed signals (ECG and heart
rate course) in separated windows. Change the position or adjust the length of
the chest belt if necessary.
(f)
If OK, Start the examination by
clicking on Start icon (or open
Control submenu and select Start
or press CTRL + S or click the
Start control button at the bottom).
Important notice: If for any reason it is necessary to record full-time ECG
record throughout the whole examination, please choose this special option in the
Control submenu -> Start with whole ECG, instead of clicking the Start icon
shown above.
(g)
Note that -- when properly started - Icons setting changes consistently, i.e., Start icon is disabled
and Stop icon along with other
icons related to current program
step are enabled. The same is valid for Measuring Control buttons at the
window bottom (Start, Stop, Save, Browse and ECG).
(h)
Additionally, in Basic values section (object No 9, see chapter 6.1. Spectral
test measuring screen) information is displayed on: instantaneous Pulse
number, Length of R-R interval, Heart rate and Time elapsed since pressing
the Start button.
(i)
Also, information on the transmitter battery status and on system
functions are displayed (objects No 5 & 6). Automatic artefact recognition
and data correction procedure starts now, as well, showing continuously
updated number of processed artefacts in Artefact record session. If
possible, leave the examination room now and perform the further
examination control / program steps from a separate room.
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(j) At the right-hand side & bottom of the screen, 3 new ‘on-line’ windows display:
• Window ‘TF5 Online HR’ displays the course of heart rate against time within
the recent approx 100 pulses (accordingly to the currently adjusted window size)
• Window ‘TF5 Online ECG’ displays single-channel ECG (time resolution 500 Hz).
It is possible to adjust the signal displaying speed and zooming by ‘drag-anddrop’ with PC mouse (like in most other windows in the program).
• Window ‘TF5 Online Spectrum’ displays the instantaneous spectral curve based
on recent 32 / 64 / 128 or 256 heart beats. This option has no influence on the
performance of the statistics after the examination is finished and serves only for
displaying the spectral curve during the measurement. Also here, it is possible to
adjust the spectral curve window and zooming by ‘drag-and-drop’ with PC mouse.
Additionally, two - blue and green - columns showing the instantaneous
‘sympathovagal’ balance / spectral power distribution between low (0.05-0.15
Hz) and high (0.15-0.40 Hz) frequency bands can be found here.
• Note: The first on-line spectral curve and sympathovagal balance graphics
appear on the monitor only after the chosen number of pulses is reached (32
pulses being the minimum). In the case above a 64 pulses-window is chosen.
All these ‘online windows’ can be
switched off/on (see the icons) and
are fully resizable to allow the user
full flexibility to adjust the screen
accordingly to her/his needs. Default positions can be quickly adjusted by
clicking the icon Default windows display or pressing CTRL + D.
(k)
When the subject’s preparatory
phase is finished, Mark beginning
of the first examination interval (or
press CTRL + M or open submenu
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Control -> Mark or click the Mark button in the Statistic interval session). Only
at this point +300 seconds/+300 pulses -- whichever takes longer -- the data
will be included in the final statistical analysis (see also Statistic interval
session No 10). Data obtained before and after this examination interval are
displayed in the 3-D graphics but not included in the statistical analysis.
(l)
Statistic interval section (No 10, for details see chapter 6.1. Spectrum
measuring screen) is now activated, additionally: examination interval number
is shown (normally 1 – 3, corresponding with examination procedure in 1supine /2-standing /3-supine), and countdown for Time and number of Pulses
remaining -- both starting from 300 downwards -- run.
(m)
It is possible to record single-channel
ECG strips as necessary, within the
whole examination process. By
pressing ECG record icon (or clicking
the Record button within the session /Record ECG session No 7/ or pressing
CTRL + E or through program submenu Control -> ECG Record) a 30 second
strip is recorded (–10 sec / +20 sec from the event). Red button in this
section shows ECG strip recording, green button ECG recording not operating
at present. In case of choosing the whole examination ECG record (see step
/f/ in this chapter) this option is disabled.
(n)
Once the 1st interval countdown is finished by reaching 0, Interval count ‘1’
appears in the Statistic interval session and time/pulse countdowns disappear.
In this moment you can request subject for active change of position – from
supine to standing. Be aware that some seniors might need a help at this
moment.
(o)
Once subject is stable and his heart rate does not display artefacts or extreme
changes related to the position change, Mark the beginning of the second
examination interval (return to step /j/ and follow the above listed procedure).
Please be aware that one of the most relevant conditions for successful HRV
data analysis is its stability (data ‘stationarity’). Therefore, wait for a while
after position change before you mark the next interval.
(p)
Once the 2nd interval countdown is finished by reaching 0, Interval count ‘2’
appears in the Statistic interval section and time/pulse countdowns disappear.
Again the subject can be requested to change position – from standing back
to supine again. Afterwards, mark the third examination interval.
(r)
After successful data collection Stop
the measuring phase by clicking on
Stop icon or open submenu Control -> Stop or press CTRL + P or click
the Stop control button at the window bottom.
(p)
Remember, please, to immediately save the collected data (click Save
icon or Save control button or Save command in main menu).
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6.2.3. Measurements: What to Do After the Examination
Ensure that you have finished the recording
correctly, i.e., after the 3rd examination
interval (Statistic interval count = 3), by
clicking Stop icon or via submenu Control -> Stop or pressing CTRL + P or clicking the Stop control button at the bottom.
Save the record immediately (click Save icon or Save control button or Save
command in main menu)! Further steps lead to browsing the record and to analysis.
6.3. How to Browse/Edit the Data
Before considering the results, check the integrity of the recorded data and remove
any artefacts as necessary (by accepting/rejecting automatic recognition procedures
and/or manually). Records that contain non-processable artefacts should be deemed
as invalid and in these cases, the examination should be repeated. The same
pertains in the final statistics table if excessive non-stationary parameters are found
(i.e., statistical relative deviation exceeds approx. 20-30% in older population or
approx. 30-40% in younger subjects).
Click the Browse icon or open Browse
option -> select Browse spectrum or
press CTRL+B keys together. A new
window (Browser) opens that consists
of several sections:
6.3.1. Browser Structure
Browser commands menu
Browser commands icons
Overview display of whole examination heart rate time course
Heart rate detailed window corresponding with the selection as in above
window. Clicking on a selected bar in the HR detail window shows at the bottom
information on the instantaneous pulse number, pulse rate and time relapsed
since the beginning of examination.
(5) Optional window displays ECG strip related to the event (artefact). This window
displays the short ECG strip only if it is automatically recorded. A standard ECG
browser can be activated in other program sessions.
(6) Artefacts processing optional window
(1)
(2)
(3)
(4)
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When browsing the heart rate record you can
• either move the selection window within the examination overview – using left
mouse button and ‘drag-and-drop’ method in the window examination overview
(section 3), whilst the selected heart rate part displays “zoomed” in more detail in
the window below (section 4)
• or click on the sliders at the left or right-hand side of the detailed window
(section 4) to scroll the HR data. This enables one to check the record
thoroughly, however, it takes slightly more time.
5&6
Additionally, in the heart rate overview (section 3) or detailed (section 4)
windows the following markers of various colours can be found:
• Green marker – shows the beginning of each examination interval that is
included into the final statistical analysis
• Red marker – indicates artefacts automatically recognised and recorded with
corresponding 6-second ECG strip during the data collection. Artefact in form of
red heart beat vertical bar(s) is displayed in the HR detailed window (section 4)
and corresponding ECG strip -- as stored automatically during the examination -in the window below (section 5).
• Violet marker – corresponds with 30-seconds ECG record as obtained during
the examination. This data can be browsed simultaneously in a separate standard
ECG Browser, for example see below:
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Practical example: HR browser showing automatically recorded
artefact caused by ectopic beat (check section 5), proposed data
correction (section 6) and ECG browser located over the HR
browser window showing the long ECG strip (whole examination).
You can switch between both browsers to view details, as well.
•
•
•
•
6.3.2. How to Find and Process Artefacts
Window HR overview (section 3): Find the automatically recorded artefact (red
marker) in the HR overview. Move the selection window onto the red marker
(‘drag-and-drop’ the window with left mouse button).
Window HR detail (section 4): Selected HR course is displayed. Click the left
mouse button and/or ‘drag’ over the artefacts to the right or left to mark them if
necessary = if not completely detected/marked by program yet (red colour bar).
The same procedure with right mouse button unmarks them (blue colour, again).
Window ECG strip (section 5) shows
corresponding ECG data while
Window
Artefacts
processing
(section
6)
shows
generated
corrections in heart rate in dark blue
colour based on calculations algorithm
over surrounding normal heart beats.
Check
the
proposed
artefact
correction and mark/unmark the
artefact portion in the section 4 if
necessary. In general, the heart rate
course should be smooth (we suggest
the exclusion of ectopic beats, as
well, see the figure).
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•
•
Progress to other artefacts and use the same procedure. Once satisfied with
artefacts processing, press the Save icon or Save
command in the menu. For the final analysis, only
‘edited/filtered’ data can be used. Be aware,
please, that even one single artefact can totally
destroy the quality of the results.
However, it is still possible to view the original
file, as well. Click the ‘Load original data’ icon (or
open ‘Load’ command and select Original data or
press CTRL+O together). Similarly, you can return
to the ‘filtered’ file – click on icon ‘Load filtered
data’ (or open ‘Load’ command and select Filtered data or press CTRL+F
together). The computer stores separately the latest processed file as a ‘filtered’
one while the ‘original’ file remains unchanged. Date (time point) of current file
editing/filtering along with the date of original record are stored, and this data is
available in the Report.
6.3.1. ECG Browser
It is possible to view either the 30-seconds long single-channel ECG strip(s) or the
whole examination ECG record as recorded during the examination session, in a
separate window. You can open it in
(a) Spectral test measuring session: click the ECG browse icon
that is available immediately after the HR record has been saved (or open the
Browse menu and select Browse ECG command or press CTRL + C together), or
(b) HR Browser session: click the ECG browse icon (or command), or
(c) Basic operation screen: select the subject and record (small arrow at the lefthand side), click the ECG browse icon (or Browsing main menu, command ECG
or CTRL + E together)
Structure of the ECG browser is simple:
• Window
heading
shows
personal data, date & time of
ECG recording
• Five strips displaying ECG
course from –10 until +20
seconds from pressing the ECG
record button (time 0, violet
marker)
• Bottom
line
includes
information on number of R-R
interval, marker time location on
the heart rate course axis,
present number and total
number of recorded ECG files,
and ‘Close’ button.
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Its main function is to enable viewing the ECG record and to support decision
making processes while browsing the heart rate course record and considering
possible artefacts.
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7. Clinical Use of the System: Analysis
7.1. HRV Basics. How to Understand the Principles of Analysis
In general, it is recommended to perform (and to understand) the examination as a
view on cardiovascular autonomic regulations during a modified orthostatic
load. This scheme allows assessment not only of the energy contents of the
autonomic control during well-defined examination positions, but also disturbances
in its dynamics. Therefore, both the absolute numbers in the statistics table and the
changes/behaviour in autonomic control as displayed in the three-dimensional
graphics are relevant for diagnostic resumes.
Spontaneous beat-to-beat fluctuations in heart rate reflect ongoing modulation of
sinus node activity through several cardiovascular control mechanisms. In addition to
the respiratory sinus arrhythmia (0.2 – 0.3 Hz), the heart rate typically oscillates at
specific lower frequencies, most commonly at about 0.05 - 0.15 Hz and lower, as
well. All these heart rate fluctuations can be quantified by the technique of power
spectrum analysis, which calculates the frequency content of time-varying signals.
Power spectra are quantified by measuring the area under the spectral curve
(Spectral Power) and its density/amplitude (Power Spectrum Density) in two/three
frequency bands (see the figure below; frequency axis 0.00 - 0.40 Hz, displayed spectrum
range 0.05 - 0.40 Hz):
•
Very-Low Frequency (VLF; 0.02 – 0.05 Hz) /not included in this fig./ and/or
o Low Frequency (LF; 0.05 – 0.15 Hz) components of spectral
energy reflect sympathetic-thermo-regulation influence with a
certain parasympathetic modulation, and
' High Frequency (HF; usually 0.15-0.40 Hz) component
reflects parasympathetic influence. The ratio of LF to HF is
mostly considered to be an indicator of sympathovagal
balance.
supine
standing
supine
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In the VariaCardio TF5, power spectra are calculated by computing the magnitude
squared of the fast Fourier transform based on data points obtained from 300
seconds’ tachometer signal. As in any biological process, the data contain both
harmonic and non-harmonic information, therefore no filtration of specific (‘chaotic’)
parts of the information is used. The total power is then obtained by integrating the
power spectrum from 0.02 to 0.40 Hz, the respective components of spectrum (VLF,
LF & HF) represent then in the above mentioned frequency bands. Power at
frequencies below 0.02 Hz should be probably not considered because it may not be
reliably measured within data records 300 seconds long. (e.g., in case of less than
0.01 Hz the wave length is then more than 100 sec., i.e. energy of only a couple of
cycles during one position recording is quantified).
Based on the length of record analysed, this kind of spectral analysis is also called a
“short--term“ analysis; the spectral power can be viewed as the variance in heart
rate during the 300 seconds periods. The “long--term“ spectral analyses are
represented by analyses using 24h Holter recordings. However, to our current
knowledge, none of the standard 24-hour Holter monitors does have a sampling
frequency high enough to offer adequate analysis.
Short-term spectral analysis of HRV is practical and easily applied in the clinic. It
was found that the immediate variability of short-term spectral measures of HRV was
low, and short, 2- to 15-minute samples were found to be excellent predictors of
mortality and correlated with prognostically important data from sustained recording
periods. Due to this simplification, patients could accept more consecutive
measurement series during longitudinal studies, as well. The method takes only a
short time and is quite independent of the patient’s compliance during the
examination. In contrast to the less sensitive total Ewing standard score of
cardiovascular reflex battery, the selected cumulative indices over more than one
time segments (e.g., in positions supine-standing-supine) proved to be able to assess
even small changes in cardiac autonomic supply.
The current methods most commonly used for analysis of HRV in frequency domain
are based either on fast Fourier transform or on auto-regressive model. Under
various conditions, both analytical approaches deliver similar results. As the
examinations are commonly performed under routine clinical conditions requiring
immediate results, system using fast Fourier transform analysis has the
advantage of sufficient simplicity of well defined algorithms, high processing speed
and on-line graphic display modality. Although the information given by the spectral
indices corresponds to that given by indices of time-domain analysis, it was shown
that cumulative index is more representative of the actual global state of
autonomic regulation and reflects the total instantaneous sympathetic and
parasympathetic effects.
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7.2. HRV Basics. How the R-R Intervals Measurement Works
shows two typical peaks of LF and HF bands.
Surface ECG is continuously
monitored and R-R intervals are
measured with a time resolution of
1 ms and further processed by
microprocessor in the transmitter
unit. The ECG and R-R data are
telemetrically transferred to a
receiver connected to a PCcompatible computer.
The ECG signal and computed
heart rate is displayed after each
heart beat on the monitor in form
of a vertical bar graph with
numerical information on current
heart rate, R-R interval length and
time elapsed since the beginning
of measurement in a separate
window.
Instantaneous (online) spectral
curve based on the last 32, 64
(see the figure), 128 or 256 beats
is displayed as well. The figure
The automatic artefact recognition of the received data is processed on a realtime basis and displayed on the monitor. When recording has finished, the original
data set is stored and then automatically filtered, excluding the recorded artefacts
using a special recognition algorithm. Finally, there is a possibility to filter the file
manually as well. Therefore, there are two files stored (‘original’ and ‘filtered’
ones) related to one data set.
For better understanding why the artefact processing is that important, see
the figures below:
• The left figure shows the spectrum created on data including one single
artefact around the time point 640 seconds (see the Browser -- upper right
window).
• The right figure shows spectrum based on the same dataset, however,
with the artefact rejected and substituted by a computed data hat is
consistent with the current data time series.
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Artefact
No
artefact
7.3. HRV Basics. How to Understand the 3D Results
The computational method of spectral analysis is based on a fast Fourier transform.
The final results are immediately displayed on the monitor as a three-dimensional
running spectrum, permitting a general overview of the dynamics and of the
absolute energy content of the system. All parameters are computed for each time
segment: within the high frequency band (0,15-0,40 Hz, attributed exclusively to
parasympathetic tone), the low-frequency band (0,05-0,15 Hz) and very-low
frequency band (0,02-0,05 Hz, shown to represent a combination of sympathetic and
parasympathetic effects and others like thermoregulation etc. on cardiac autonomic
tone). The autonomic control varies under different physiological states, typically
during a modified orthostatic load: the parasympathetic component is predominant in
supine position, while the sympathetic one during active standing.
The main outcome variables in frequency domain are:
• Absolute spectral power (units [ms2]) and
• Power spectral density (units [ms2/Hz]) in two or three frequency bands
and their
• Ratios VLF/LF and LF/HF bands
• Mean frequency (units [mHz]) for each frequency band
• Cumulative spectral power: to increase the reliability of the short-term
measurements and to assess even small intra-individual differences in global
autonomic tone, the cumulative index (spectral power of the total
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•
frequency band with its very-low, low and high frequency over all recorded
positions; units [ms2]) representing the total averaged area under all
consecutive spectral curves within the short-term recording is calculated
Standard deviations (units [%]): calculated for each parameter, as this
information is necessary for assessment of the ‘stationarity’ of the
examination. We recommend excluding any findings having more than 2030% relative deviation in any of the time segments recorded. In those cases,
the examinations should be repeated
Additionally, calculations of time-domain parameters are made, as well:
♦ Mean R-R interval (NN mean)
♦ Standard deviation of mean R-R interval (SDNN)
♦ MSSD (Mean of the squared differences between two adjacent normal R-R
intervals over given recording period)
It is possible to display the results in three different display options, as:
(1) Three-dimensional running spectra graph (see Chapter 7.4. How to Perform
the Analysis)
(2) Statistical table (‘Numerical spectral results’)
(3) Graphical form (‘Graphical spectral results’).
Practical example: The figure above shows results options (2) and (3),
based on normal cardiac autonomic control as obtained during modified
orthostatic load: the numerical data displayed correspond with the above
listed main outcome variables, the graphical output displays absolute values of
spectral powers LF & HF in (three) examination intervals. It documents
predominance of HF band (right column, in green) in supine -- intervals 1 and
3 -- and predominance of LF band (left column, in blue) in standing positions - interval 2.
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7.4. Analysis. How to Perform the Analysis
First select the subject for the analysis
from the Subjects listing in the
basic operation screen (see Chapter
5.4. Database: How to Find a Subject).
Optionally, then open the Browser – click on icon
-- and check the
consistency of the R-R data, particularly with respect to artefacts. If artefact found,
process it properly – see the Chapter 6.3.2. How to find and process artefacts. Bear
in mind, please, that even one artefact might totally destroy the quality of
information received over the total 15 minutes measurement.
However, you can also directly progress to the 3D analysis: click on icon Frequency
or press CTRL + F together or in the main program menu
domain analysis
open Analysis -> Frequency domain. Following Basic analysis screen is opened:
7.4.1. Basic Analysis Screen. 3D Running Spectra Graph
Practical example shows a typical pattern obtained in a subject with no detected
disturbances in cardiovascular autonomic control during a modified orthostatic test
(lying down [T1] - standing up [T2] - lying down [T3], calculation for every position is
based on 256 artefact-free data points; note that this display includes only low and
high-frequency bands /range adjustable in the Engineering->Program Setup/). The
graphics shows clearly a predominance of HF band (0.15-0.40 Hz) during supine
positions (marked as T1 and T3) while LF band (0.05-0.15 Hz) gets ‘activated’ during
standing-up (marked as T2). The numbers 1-8 are related to its detailed description,
see below.
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The standard Basic analysis screen of the measurements includes:
(1) Windows heading includes subject’s last name, year of birth and recording
time details of the record analysed.
(2) Below, a line with Program sub-menu commands include options View
(Statistical table or Graphical output), Resume (allows to write comments on
the results), Output (Printing or Export of the results in text format) and
Exit.
(3) Icons enabling quick access to the most of above functions.
(4) Two-dimensional spectral graph that shows single spectral curve created
at specific time point – see the ‘slider’ at the right-hand side of the output
screen. An instantaneous sympathovagal balance ‘online’ chart (is displayed
right along the 2D spectral curve (blue & green bars).
(5) The biggest part of the screen covers three-dimensional running spectra
graph showing the behaviour of the autonomic cardiac control system during
the whole examination. Note, please, that while this display shows the
complete record including the changes of position etc., the final statistical
results are based only on 0 - 300 seconds periods from pressing the marker in
each position (see markers T1, T2 and T3).
(6) Zoom control slider allows to adjust the size of the displayed graph.
(7) Time control slider allows to ‘slide’ the graph while showing instantaneous
spectral curve at specific time point (‘slice time’). This interval is displayed in
[seconds] from the start of measurements (and not from pressing any of the
markers!) below the slider.
(8) View control pointer at the left lower corner below allows to adjust the view
angle of the 3D graph in order to enable better overview over the results.
Practical example: Below you can find some examples of 3D display manipulation
using the ‘View control’ option, in order to obtain an optimum graphical overview
of the autonomic control during the modified orthostatic test.
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7.4.2. Basic Analysis Screen. Statistical Table
The results can be obtained in
form
of
the
Numerical
spectral results table that is
reached by clicking on the first
icon
in
the
Submenu
commands line.
The table is vertically divided
into three sections covering 3
measurement intervals (supine/
standing/ supine). Horizontally,
groups of parameters are
shown
where
the
most
important information includes
the
(Spectral)
Power
variable, displaying power within specific frequency bands.
Above in the Statistical table you can see results of short-term HRV spectral
analysis as obtained in a normal subject (see also Chapter 7.3. HRV Basics):
• Variables Power LF and HF represent low and high frequency bands here.
• Variables PSD mean Power Spectral Density, in both frequency bands.
• Freq. shows the mean frequency within the specific bands.
• Rat. LF/HF displays interconnections between low and high frequency band
spectra in all positions separately. Some authors declare this variable as
‘sympathovagal balance’.
• Total power sums the LF and HF powers.
• Cumulative total power shows sum of three total power variables above.
• NN mean shows a mean value of R-R intervals within the position.
• SDNN standard deviation of mean R-R interval.
• MSSD shows Mean of the squared differences between two adjacent normal
R-R intervals over recording position.
7.4.3. Basic Analysis Screen. Graphical Table
Also, there is a possibility to
obtain a quick overview of
the results in a graphical
form (Graphical spectral
results table), by clicking
on the first icon in the
Submenu commands line.
The chart shows distribution
of LF and HF spectral
powers related to each
examination interval, here
shown as 1, 2, 3. On the
left-hand
axis
absolute
value of the parameters can
be found (unit [ms2]).
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Important notice:
Please note that for the statistics, only those 300 seconds’ time intervals marked
previously in the measurement session are included. Check the Browser, please,
where the start of statistical intervals is marked in green. This can sometimes
‘optically’ diverge from the graphically displayed results.
7.4.4. Basic Analysis Screen. Resume
For reporting, comments on the
HRV analysis results prepared
by medical professional might
be necessary. For this reason,
an option Resume allows to
enter and store record-specific
texts related to any part of the
examination procedure.
Click on icon or in the program
submenu open the Resume
option. In the window, type in
your texts. Alternatively, you
can use pre-defined text
patterns as prepared in the Main program menu, Engineering -> Program setup
menu -> Default resume option.
When finished, please be sure to save the created texts and close the window. This
Resume text appears in the printed Report, as described below.
7.4.5. Basic Analysis Screen. Export of Numerical Results
For various reasons, the export of results in digital form might be necessary. In such
case click, please, on the icon or open in the Program submenu the option Output > Data export. A text table ‘export.txt’ (located in the TF5 program directory or as
adjusted in the Engineering -> Program Setup -> Export/Send menu) is then
created which includes consecutively listed following variables as originally displayed
in the Numerical spectral results table, separated by ‘;’:
id; name; date; Power LF 1 [ms2]; Power LF 1 variance [%]; Power HF 1
[ms2]; Power HF 1 variance [%]; PSD LF 1 [ms2/Hz]; PSD LF 1 variance [%]; PSD
HF 1 [ms2/Hz]; PSD HF 1 variance [%]; Freq. LF 1 [mHz]; Freq. LF 1 variance [%];
Freq. HF 1 [mHz]; Freq. HF 1 variance [%]; Rat. LF/HF 1 [-]; Rat. LF/HF 1 variance
[%]; R-R inter. 1 [ms]; R-R inter. 1 variance [%]; Total power 1 [ms2]; Cumulative
total power [ms2];
Power LF 2 [ms2]; Power LF 2 variance [%]; Power HF 2 [ms2]; Power HF 2
variance [%]; PSD LF 2 [ms2/Hz]; PSD LF 2 variance [%]; PSD HF 2 [ms2/Hz]; PSD
HF 2 variance [%]; Freq. LF 2 [mHz]; Freq. LF 2 variance [%]; Freq. HF 2 [mHz];
Freq. HF 2 variance [%]; Rat. LF/HF 2 [-]; Rat. LF/HF 2 variance [%]; R-R inter. 2
[ms]; R-R inter. 2 variance [%]; Total power 2 [ms2];
Power LF 3 [ms2]; Power LF 3 variance [%]; Power HF 3 [ms2]; Power HF 3
variance [%]; PSD LF 3 [ms2/Hz]; PSD LF 3 variance [%]; PSD HF 3 [ms2/Hz]; PSD
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HF 3 variance [%]; Freq. LF 3 [mHz]; Freq. LF 3 variance [%]; Freq. HF 3 [mHz];
Freq. HF 3 variance [%]; Rat. LF/HF 3 [-]; Rat. LF/HF 3 variance [%]; R-R inter. 3
[ms]; R-R inter. 3 variance [%]; Total power 3 [ms2];
The recently edited results are consecutively added to the previous one into one text
file, line by line. I.e., whenever numerical results data of any subject are exported,
these numbers appear in the ‘export.txt’ file, in the next line.
7.5. Analysis. Medical Report and How to Obtain It
Detailed medical reports including the graphical and numerical information obtained
during the HRV measurements, completed by personal data details and summary
prepared by the examiner/reviewer can be printed from the Basic analysis screen
session after pressing the Print icon or by following in the Program submenu the
option Output -> Print protocol or by pressing CTRL + P.
Medical report includes following main sections:
Page 1 of the Report
(1)
Organisation / Reporting physician details (adjustable in the Main program
menu -> Engineering -> Program Setup -> Print Attribute)
(2)
Subject’s personal data
(3)
Record
technical
information including
number of artefacts
and ECG records
(4)
Written resume – as/if
prepared by reporting
physician (text can be
entered in the Basic
analysis screen ->
Resume) -- followed
by the date of analysis,
printing and name of
reporting physician.
(5)
Below, at the bottom
line technical data on current system installation are included.
Page 2 of the Report
(6)
Graphical 3D running spectra output including the last name, year of birth
and recording details in the figure heading. Note that the printout is
‘interactive’ as it corresponds with the current view angle of 3D graphical
output as just adjusted.
(7)
Statistical table including all variables originally displayed in the Numerical
spectral results
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8. Battery of Short Cardiovascular Reflex Tests as Proposed by
Ewing (so-called ‘Ewing battery’)
8.1. Ewing Battery: Introduction
This battery of cardiovascular bedside reflex tests consists of three/four functional
tests of heart rate variability, for details see below. The obtained results are then
analysed in time-domain as proposed by DJ Ewing (e.g., see DJ Ewing et al: The
Value of Cardiovascular Autonomic Function Tests: 10 Years Experience in Diabetes.
Diabetes Care 1985, Vol.8, No.5; 491-498). The tests have been suggested to be
suitable for a clinical routine screening (‘gold standard’), although they
predominantly represent vagal function information, are semi-quantitative only, and
probably do not detect sufficiently those early stages of autonomic dysfunction that
usually are modifiable by various interventions.
8.2. How to Perform the Ewing’s Test Battery
In the basic operation screen, click on icon Measuring
(or press CTRL + E or
open Measuring option in the main program menu and select Ewing’s Test).
New screen Ewing’s test measuring is displayed with following main sessions:
1. Commands menu including submenu
items Control, Save, Results, Window and
Exit.
2. Icons menu corresponding with the
above, including additionally Start and
5&6
Stop,
Save,
Browse
the
results,
Display/Hide specific windows, for details
see below.
3. Subject
identification
with
ID,
Surname and Date of birth items.
4. Hardware info shows the current quality
of data transfer/ECG in left window and
progress of heart rate over recent time in
the right window.
10
5. Radio signal quality indicator, and
Battery status show current state of
these items.
11
6. Alert window below the radio signal and
battery status indicators informs you of
12
system configuration and of possible
errors (e.g., alert ‘Receiver switched
off...’). A strip with information “OK”
13
shows normal setting, strip blinking in
orange warns of errors and possible cause of the problem encountered is displayed.
Furthermore, pre-defined user’s limits – in accordance with pre-set/prepaid service – and
currently available number of TF5 test actions are shown.
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7. Blood pressure values can be optionally entered before and after the Valsalva
maneuver and Deep breathing tests. These BP values are, however, required for correct
consideration of results during the orthostatic test.
8. Basic values window delivers exact numeric information on instantaneous R-R data:
Time elapsed since pressing ‘Test start’ button in [min:sec], Length of R-R interval in
[ms] and Heart rate in [beats per minute].
9. Test selection menu enables to choose among the tests: deep breathing, Valsalva or
orthostatic load.
10. Test progress bar is an optical hint showing progress of the test in form of constantly
growing ‘line’ / small squares.
11. Breathing guide bar is used for guiding/support of correct & reproducible deep
breathing pattern.
12. Help alerts can be seen in well readable big letters in a yellow bar as indicated above.
Commands shown here can be used as guides for correct/standardised performing the
tests. Additionally, corresponding voice commands can be heard paralelly.
13. Measuring control buttons at the bottom of the window control program functions
such as Save and Results. Compared to the spectral analysis section, here is no need to
use Stop buttons as the test ends automatically in accordance with standardised test
protocol. An alert/help & voice messages inform about the end of each test.
In the Test selection menu (section 9, see above) in the measuring screen click on
appropriate button, that allows you to perform one of the three reflex tests:
(1) Deep breathing - heart rate changes during four deep breathing cycles are recorded,
each of them consisting of 5 sec. inspiration and 5 sec. expiration. After four breathing
cycles are completed, test ends automatically.
(2) Valsalva manoeuvre - tests heart rate changes following a deep inspiration and 15seconds expiration against 40 mmHg pressure. As reported, it is recommended to
perform this test three times in one measurement session (or to perform one “test“
measurement at least before the recording, in order to demonstrate the exact test
procedure for the patient).
(3) Orthostatic test - changes of heart rate and blood pressure (separately, using a
common BP measurement device) during supine position, and, during the first 30
seconds, HR changes and/or some 2 - 5 minutes BP changes after standing up are
recorded.
To perform any of the individual tests, see the following description. The help function at the
bottom of the screen offers information and hints as to how to proceed. After starting the
test, the elapsed time interval since the beginning of the test, R-R interval length and the
instantaneous heart rate are displayed.
Generally, before starting the first test, you have to choose / add a new test subject in
the program database. For details, refer to the Chapter ‘How to find a subject’ or ‘How to
add a new subject’, please. Afterwards, in the Main menu progress to Measuring ->
Ewing’s Test (alternatively press CTRL+E together or click on the icon). If the transmitter is
already correctly positioned on the subjects’s chest and it is switched ‘on’, you will already
have an option to check the quality of transmitted data in the hardware info windows
(section 4, see above). This option is identical with the function in the spectrum measuring
screen. If the displays are satisfactory, progress to the first Ewing’s test:
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8.2.1. Ewing Battery: How to Perform the Deep Breathing Test
The subject sits quietly on the examination bed, the thorax belt with integral
electrodes is correctly positioned on the chest and the transmitter switched on
(regular signals as indicated by the LED-diode are detected).
Click on the Deep breathing test button (section 9 in the measuring screen). Enter
the blood pressure value, if needed (optional). Then click on the ‘Test start’ button - see below, the screen shows effect of a cyclical breathing on the heart rate course
while voice and written / graphical commands help to guide the test appropriately:
After an initial phase (10 seconds) that is necessary for obtaining basic data for
statistics, a voice and written command “Breath in” appears, followed after 5
seconds by “Breath out” command. Paralelly, a breathing guide bar slowly increases
and decreases in green so that the subject’s cyclical breathing excursions are
maximally standardised, each of them 5 seconds (four inspirations and four
exspirations). When finished (after 40 seconds), a message appears on the screen:
“Breath normally”. Another 10 seconds of data are then
recorded for computational purposes, a final longer beep
and messages “Test is finished” indicate that the test is
finished automatically.
Important notice: the record
must be absolutely artefact-free in order to ensure reliable
test results. (See “Filtration“ procedure)
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After the measurement is finished, the following procedures/keys can be used:
After any of the Ewing’s tests is finished, save, please, (by clicking on the ‘Save’
button below) the recorded data immediately. Afterwards, the patient’s record and
identification information is displayed, as well as graphics displaying the heart rate
course during the whole test and all relevant statistical results – click on the
‘Results’ button below.
Relevant parameters: Deep breathing test
HRrest :
MV:
SD:
MSSD:
CVr-r :
I-E:
I/E:
Resting heart rate
Average R-R interval
Standard deviation
Mean Square of Differences of Successive R-R Intervals
Component Variance of R-R Intervals
Difference Inspirium and Expirium heart rate
Ratio maximum vers. minimum heart rate during Inspirium
and Expirium
Practical example: Typical results screen with apparently normal heart
rate variability during the deep breathing test. For parameters
description, see above. The green lines in the main screen show time
course of test commands (5-seconds cycles), ECG below, position of the
browser of heart rate course and numbers shown at the bottom line are
related to the marked HR value – in yellow, see the main screen. In
order to remove artefacts, the marking can be changed by moving the
mouse and clicking the left (mark) or right (unmark) buttons. This
procedure is identical with that used in spectral analysis processing, as
described earlier.
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8.2.2. Ewing Battery: How to Perform the Valsalva Maneuver
Choose the ‘Valsalva maneuver’ option by clicking the button. Optionally, enter the
blood pressure values and start the measurement by clicking the ‘Test start’ button.
After starting you have to wait for 10 seconds, after which a message ‘Breath in
and blow into tube’ appears. Identical voice command is heard, as well. The
patient has to inhale deeply, and when starting the exhalation (while reaching 40
mmHg on the manometer), the examiner has to press the ‘Pressure reached’ key.
Under constant resistance of 40 mmHg during the expiration, the heart rate course is
recorded for 15 seconds.
Afterwards a short signal beeps, and a message ‘Release
and breath normally’ appears, paralleled by a voice
command. The subject returns to normal breathing and has
to wait until the end of the test (some 20 seconds again).
Finally, a message ‘Test is finished’ closes the
examination. Please save the recorded data immediately,
again, by clicking the ‘Save’ button below. Results of the
test are available by clicking the ‘Results’ button below on
the screen.
Relevant parameters: Valsalva maneuver
VR
t max
t min
HRrest
HR max
HR min
HR max / HR rest
HR max - HR rest
HR min / HR rest
Valsalva-Ratio
Timepoint of maximal heart rate
Timepoint of minimal heart rate
Resting heart rate
Maximal heart rate
Minimal heart rate
Ratio maximal heart rate vers. rest
Difference maximal heart rate minus rest
Ratio minimal heart rate vers. rest
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Practical example: Above you can see a typical course of normal reaction of
heart rate during the Valsalva maneuver (blue bars) as seen during the
examination. Just a note, save always the obtained data as soon as possible to
avoid unnecessary data loss etc.
Notice: From experience, it is recommended to make three Valsalva tests, and to
express the result (the Valsalva ratio) as the mean ratio from the three successive
tests (for more details see also Ewing DJ: The Value of Cardiovascular Autonomic
Function Tests: 10 Years of Experience in Diabetes; Diabetes Care, 1985, 5: 491498).
8.2.2. Ewing Battery: How to Perform the Orthostatic Test
Whilst the subject is lying on the bed, measure his BP and – after choosing the
‘Orthostatic test’ option -- enter the values into the fields ‘Blood pressure before
the test’. Click the ‘Start’ button and wait for 10 sec (see the description above).
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After this preparatory phase, a message ‘Stand up’ appears, paralleled by a voice
command. After the subject finished the change of his position and is quietly
standing, click the button ‘Standing position reached’. The subject stands until
the automatic ending of the test. The examiner (repeatedly) measures the blood
pressure throughout the test. It is highly recommended to
enter the blood pressure values into the program at the
beginning and end of the test, as indicated on the screen.
Finally, a confirmation ‘Test is finished’ appears/is heard,
while you save the data immediately, by clicking the ‘Save’
button to be found below on the screen left.
Relevant parameters: Orthostatic test
30:15 Ratio
HR rest
HR max
HR min
HR max / HR min
HR max - HR rest
HR max / HR rest
HR min / HR rest
BP pre
t max
t min
BI
BP post:
Ratio of heart rates around the 30th & 15th beat
Rest heart rate
Maximal heart rate
Minimal heart rate
Ratio maximal heart rate vers. minimal one
Difference maximal heart rate minus rest
Ratio maximal heart rate vers. rest
Ratio minimal heart rate vers. rest
Blood pressure value during lying down
Timepoint of maximal heart rate
Timepoint of minimal heart rate
Brake Index
Blood pressure value after standing up
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9.1. Some Practical Examples
Below you can find some examples to show the versatility of applications and use of
the TF5 program just to help you in finding appropriate use of the system:
♦ E.g., it is possible to revise the previous results, while another examination is
running, and to show both paralelly on the screen.
♦ You can display all results of short reflex test (Ewing) battery on one screen, and
resize/manipulate the results windows to obtain the best overview.
♦
Also results of both analysis types – Ewing battery and spectral analysis – can be
displayed in one screen for better and instant overview of the subject’s results.
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♦ Progress of the individual test results overt longer time period can be shown e.g.,
as follows.
9.2. Application Notes
Examination of heart rate variability has considerable potential to assess the role of
autonomic nervous system fluctuations in normal healthy individuals and in those
with various cardiovascular and non-cardiovascular disorders. Population based
clinical trials show that the short-term examination of HRV, particularly in frequency
domain, offers relevant prognostic information independent of and beyond that
provided by traditional risk factors. Depressed HRV is a predictor of mortality and
arrhythmic complications, however, like in any other method, to improve the
predictive value HRV can be combined with other factors, e.g. LV ejection fraction in
post-myocardial infarction risk stratification etc.
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General Picture:
During the modified orthostatic load (provided it is performed as recommended in
the user manual) the following characteristics are of particular interest:
(a) Three-dimensional graphics:
( Total energy contents (fluctuations) of the low and high frequency bands
( Physiological predominance of both control sub-systems during different positions
( Reactivity/reflexivity of the system during the standing up and after lying down.
SY(+PASY)
PASY
Principally, the area under the fluctuations to the left from 0.15 Hz on the x-axis
represents the sympathetic activity including probably a certain amount of
parasympathetic influence. Fluctuations to the right from the arbitrary limit 0.15 Hz
on the frequency axis reflect solely the parasympathetic cardiovascular control.
(b) Statistical table:
It is often helpful to compare the visual results with the numerical values as listed in
the statistical table (see user manual). Please note that there is a strong relationship
between age and normal reference range which considerable diminishes with
severity of disturbance (described later in this chapter).
Normally, during supine positions (the first and third time intervals, labelled T1 and
T3 on the z-axis) there is a predominance of a parasympathetic tone, as indicated in
the above graph labelled “PASY“. During standing (position T2), activation of the
sympathetic tone can be detected (labelled “SY“).
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Your Notes:
In case of any comments and/or questions, please feel free to contact your
distributor, or the manufacturer directly:
Advanced Medical Diagnostics Group Ltd.
6, Wortley Moor Road,
Leeds, LS12 4JF
United Kingdom
Phone: +44 (0)113 279 1010
Fax:
+44 (0)113 231 0820
Website: http://www.amdgmedical.com
http://www.mie-uk.com
E-Mail: TF5@amdgmedical.com
Thank you.
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