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SIMPLE, INEXPENSIVE HEART RATE MONITOR AND ARRHYTHMIA DETECTOR FOR USE IN TOXICOLOGICAL STUDIES
Citation:
Watkinson, W. AND J. Ali. SIMPLE, INEXPENSIVE HEART RATE MONITOR AND ARRHYTHMIA DETECTOR FOR USE IN TOXICOLOGICAL STUDIES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/084, 1993.
Description:
Many toxic agents have been reported to produce acute, adverse effects on cardiac function. Often these data are neglected in toxicological studies because of the difficulty and expense of monitoring cardiac parameters. We have developed a simple, inexpensive heart rate monitor (HRM) capable of continuously quantitating and displaying steady state heart rate (HR) while simultaneously detecting the occurrence of arrhythmic events. This device incorporates many operator-selectable features designed to promote maximum versatility and use with a number of animal species over a variety of experimental conditions. The HR is computed from the electrocardiogram (ECG) using the reciprocal of the analog integration of the R-R interval. Adjustable trigger level and input polarity controls are provided to optimize compatibility with the ECG signal. A high pass filter is employed to accommodate minor excursions in the signal baseline and a precision rate generator is provided for calibration purposes. The HRM can accurately measure HR's over a range of 60-800 bpm. Arrhythmias are identified using an analog circuit technique which compares ECG cycle lengths to determine the relative change between consecutive ECG complexes. This device can be readily constructed from the circuit diagram and costs less than $500.00 to build. It should prove to be a useful adjunct to toxicological and pharmacological studies.