The VariaCardio® TF5: What does it measure?
 
 
The VariaCardio® TF5 uses a telemetric system of data transfer and special advanced software. Therefore, highly accurate, artefact free, R-R interval measurement with immediate graphic and statistical results of the examination are obtained.
 
 
The unit consists of an adjustable chest belt with two flat electrodes, built-in UHF-transmitter and an onboard signal analysis unit. This transmits to a UHF-receiver which is connected to an IBM-PC compatible computer via a serial port. A data collection and analysis software package enables the transmitted data to be displayed, stored and edited.The patient’s heart rate variability data and ECG can be displayed in different graphical formats and the statistical reports can be printed out on a printer.This precision instrument has been developed over 9 years and has undergone many clinical trials. It exceeds the requirements stipulated by the special task force of the European Society of Electrophysiology and the North American Society of Pacing. Numerous peer-reviewed articles have been published indicating the value, accuracy and validity of the TF5.
 
What exactly does it measure?
The primary application is to establish the risk factor of possible heart disease. This requires either statistical analysis (time domain) or Fast Fourier Transform analysis (frequency domain) and the reliability of the results relies very strongly on the quality of the data collected.

HRV has been shown in a number of clinical trials to be the best predictor of Sudden Death Syndrome and Diabetic neuropathies.

As diseases such as diabetes are related to the nervous system and many diabetics suffer from reduced cardiovascular control, HRV is of particular relevance in monitoring these patients and their treatment regimes.

Other users wish to monitor progress of disease or treatment both in early stages of cardiac degeneration and following a Myocardial Infarct. Some doctors use it to help subjects stop smoking, loose weight or encourage them to exercise. In these types of uses, the HRV monitor must be able to detect small changes over relatively short periods of time. Only the TF5 can do this with any degree of reliability and accuracy.

In order to achieve this, the TF5 ensures minimal inter and intra operator error thus providing a high degree of repeatability.

When used as a research instrument, the quality of the research results often depend on the objectivity of the measurements and their accuracy and repeatability.

The TF5 has been used in many research applications which includes the analysis of the body’s autonomic nervous system and cardiac controls in response to drug therapies.

Finally the TF5 is being used in both sports medicine and the establishment of training regimes for athletes. A number of Olympic teams use the TF5 as the measurement tool for optimising their training programmes and ensuring maximum cardiac performance at critical times.

The TF5, when used according to set protocols, is the only instrument available that is able to meet all of these demands and is the only system which collects data at a sampling rate sufficient to produce an accurate HRV analysis.
 
Is it an ECG machine?
Many people confuse HRV with ordinary ECG equipment or heart rate monitors. They see the ECG trace and assume that the TF5 is just analysing a standard ECG record. It is important to stress that the TF5 is collecting data from, and measuring, the autonomic nervous system that controls the heart rate, rather than the ECG per se.
 
 
Because the TF5 is measuring the autonomic nervous system, it is important to exclude any external factors that may affect it, such as emotional stimulation, caffeine, cardio-active drugs etc. during the data collection period It is therefore recommended that the set protocol is used to measure the HRV. This includes asking the patient to refrain from smoking, drinking alcohol, tea or coffee or taking any medication prior to the test.

Another important factor is to ensure that the patient is not disturbed during the test. It is well documented that heart rate and blood pressure can change just from the psychological stress of seeing the doctor. Likewise, the autonomic system may be affected by other influences such as someone walking into the room, distracting noises (telephone ringing or talking) or uncomfortable conditions.

To minimise these effects, it is recommended in the protocol that the patient should be in a comfortable, quiet, warm room with soft lighting. The patient should be lying on a comfortable examination bed with a pillow. After the patient has been introduced to the instrument and explained what is required from him, the examiner should leave the patient to quietly relax in the room by themself.

Only a telemetric system allows the patient to be in one room whilst the examiner and data collection system is in another room, hence creating the ideal conditions for repeatable and accurate HRV analysis.

The telemetric system also allows online data collection during exercise which is required for some of the Ewing tests and in sports applications.
 
 
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VariaCardio® and VariaPulse are registered trademarks of AMDG Ltd. This product is protected by patents owned by AMDG Ltd.

Manufactured for AMDG by MIE Medical Research Ltd (an ISO13488 accredited company). AMDG and MIE Research Ltd reserve the right to amend specifications without notice in accordance to their policy of continual product improvement.
 
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