A SYNCHRONIZER FOR ELECTROCARDIOGRAMS, PHONOCARDIOGRAMS, AND CINEANGIOCARDIOGRAPHIC STUDIES.

Abstract

In many studies to evaluate cardiovascular disease, it is desirable to synchronize the electrocardiogram and phonocardio-gram with the cineangiogram. This permits the individual film frames to be associated either with segments of the cardiac cycle or with various cardiac sounds that may be present. A simple circuit which records simultaneous pulses on both the film and the electrocardiogram has been developed and used for this purpose. The total cost of parts was less than ten dollars. The circuit (Fig. 1) is basically a neon bulb relaxation oscillator. The neon bulb is fixed along the edge of the output phosphor of the image intensifier. The position is adjusted to give minimum interference to the image on the phosphor and still remain in view of the camera. When switch S1 is closed, the neon bulb flashes at the rate of one to three times per second. Potentiometer R1 provided control on the flash frequency within this range. Simultaneously with each flash a voltage pulse appears at plug PL1. By connecting PL1 to the D.C. input jack of one channel of an EKG recorder, the synchronization pulse is recorded adjacent to the EKG or pho-nocardiogram. While switch S2 is depressed, a continuous mark (event marker) will appear on both the film and EKG. This can be used to mark the beginning of a study, injection, and other events. Summary A simple circuit which records simultaneous pulses on an electrocardiogram and cineangiogram has been developed. It has been utilized to associate individual film frames with segments of the cardiac cycle and with various cardiac sounds.