Digital computer model of a total body electrocardiographic surface map. An adult male-torso simulation with lungs.

A 20-dipole digital computer model of the electromotive surface generated by the heart with a simulated human male torso, including lungs, is presented. The simulated torso-surface ECG equipotential maps were compared to those seen in normal human subjects by Taccardi and were found to resemble them to within the resolution of these maps throughout most of ventricular depolarization (QRS). On comparison of the simulated maps to those produced when the heart was considered to be a single equivalent dipole, it was found that normal surface maps contain considerable information not accounted for by an equivalent dipole source during the mid and terminal portions of the QRS. This information occurs in areas not sampled by a standard precordial electrocardiogram. The addition of the lungs did not appear to change the surface ECG map in any important respect.