Body Surface Potential Distribution: Comparison Of Naturally And Artificially Produced Signals As Analyzed By Digital Computer

Abstract

Rapid construction of equipotential maps of the canine chest for both natural cardiac and implanted artificial dipolar generators has been demonstrated. Maps for the artificial generators revealed largely, but not consistently, symmetrical dipolar patterns. As noted elsewhere the maps for the signal from the natural, cardiac generator revealed multi-polar as well as dipolar patterns. Comparison of the maps from parallel pairs of bipolar generators showed relative attenuation of signals arising nearer the endocardium consistent with the theoretical shunting effect of the nearby intracavitary blood mass. This finding suggested local variation in intensity and orientation of any given lead vector according to the exact myocardial site. The technique of recording from many points of the thoracic surface makes possible the storage of the effect of both kinds of generator on surface potentials in a form retrievable for any lead-system. Immediate problems which are now susceptible to attack by this means are (1) lead vector assay in detail throughout the area of the active myocardium, (2) quantification of the natural signal, and (3) study of the effect on the surface distribution of potential of analogs of more complex generators than the dipole.