Abstract
The diagnosis of origin of ventricular premature beat in ECG is not yet unified. So, I performed the experimental research on the diagnosis of origin of ventricular premature beat by polyography exciting the various points of toad heart with induction stimulator. Points of lead were selected eight point on the ventral surface surrounding the heart with same distance. In some cases the direct unipolar electrocardiograms were led from epicardial and endocardial surface adjacent to stimulated point to sompare with the results of VCGs. 1) The polyograms obtained by stimulation of the corresponding epicardial and endocardial surfaces were coincided very well in their forms, directions of long axesm initial and terminal directions and rotation of QRS. loops. These findings showed that the effect of the electromotive force across the ventricular wall at stimulated point was too small to change the vectorcardiogram. I ascertained also these findings by direct unipolar lead ECGs. Namely, when I stimulated the epicardial surface and led the unipolar ECG from adjacent point to it, the tracing began with Q wave after 0.01 sec. (mean value) of latency. Stimulated the endocardial surface mear the apex and led the unipolar ECG from just above points on epicardial surface the tracing began with Q wave after 0.07 sec (mean value) of latency. On the contrary, stimulated the epicardial surface and led the unipolar ECG from subjacent endocardial surface, the tracing began also with Q wave after 0.14 sec. (mean value) of latency. Both curves were resembled very closely each other except the latency. When the endocardial surface near the base was stimulated, the ECG began with alike wave to natural one and could not be used as a critical one. 2) The initial direction of QRS loop by artificial premature ventricular beat were coincident very well with direction of inward normal at stimulated point and not with that toward the center of gravity. The direction of long axis of QRS loop coincided also relatively well with that of inward normal. 3) The initial direction of QRS loops obtained by stimulation of basal endocardial surface differed relatively in wide range from direction of inward normal. The cause of discrepancy in their direction may be the entrance of stimuli in the funneleled normal conducting tissue in relatively eary stage. 4) The terminal direction of QRS loop coincided relatively well with the direction of outward normal and countercloolwise when the left lateral wall. 7) From these findings we could diagnose the origin of ventricular premature beat, but the differentiation of it whether it came from endocardium or epicardium was impossible.
