An instrument for long term on-line studies of left ventricular function based upon a personal computer and a miniature detector

Left ventricular ejection fraction (LVEF) is a noninvasive index of left ventricular function and a useful guide to prognosis after myocardial infarction. This paper describes an instrument for recording LVEF which uses a miniature detector, small enough to be fastened to a subject's chest, and a personal computer, programmed to guide the operator's hand in placing the detector over the left ventricle and analyse the time course of the recorded activity. Electronic circuits for two detectors and a bipolar lead ECG, for triggering gated studies, are built into the computer as add-on cards. Long term studies of left ventricular function, including exercise and acute interventions, are possible as well as beat-to-beat studies. The apparatus fits on a small trolley and can easily be used at the bedside. The cost of this equipment is a small fraction of that of a gamma camera and dedicated computer. (author). 4 refs, 5 figs