Distribution of Heart Potentials on Dog's Thoracic Surface

The distribution of equipotential lines on the surface of the trunk has been determined experimentally in the dog at 8 to 15 instants of time during ventricular depolarization. Multiple potential maxima and minima are simultaneously present on the explored area during a large part of the activation time: their number, shape, and location vary continuously during ventricular excitation, following the same general scheme in all the animals studied. The single dipole theory does not account for the experimental data, reported in this paper. As far as surface potentials are concerned, the dog heart behaves as a multipolar generator. Complete exploration of the chest surface yields much more information about the electrical activity of the heart than is obtainable from routine limb and chest electrocardiograms. The relationships between the location of the potential maxima and minima on the body surface and the probable situation of the excitation waves in the heart are tentatively discussed.