A Simple, Inexpensive Heart Rate Monitor and Arrhythmia Detector for Use in Toxicological Studies

Many toxic agents have been reported to produce acute, adverse effects on cardiac function. Often these data are missing from 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 incorporated for calibration purposes. The HRM ca...