Distribution of heart potentials on the thoracic surface of normal human subjects.

• Multiple electrical recordings from the thoracic surface of the dog have recently shown that during some portions of the QRS interval only one maximum and one minimum of potential are simultaneously present on the chest wall, as one would expect from the theory of the single equivalent dipole. During larger portions of the ventricular depolarization time, however, several simultaneous maxima and minima can be observed. Such a complex distribution of surface potentials cannot be reconciled with the above-mentioned theory. A multipolar equivalent generator should be considered," in order to account for the experimental data. The complexity of the surface patterns should be referred to the existence, within the heart, of multiple, separate groups of electrically active fibers,' each group exerting a preponderant influence on certain regions of the chest surface (proximity potentials).