Instantaneous Equipotential Distribution on Surface of the Human Body for Various Instants in the Cardiac Cycle

Abstract

The instantaneous total potential distribution on the anterior and posterior surface of the body was established in 11 normal subjects for several moments during the inscription of the QRS complex. The fundamental geometric pattern of the equipotential loci exhibited the following 4 characteristics: (1) the most fundamental property of the distribution is the presence of a most positive and a most negative region of potential with the potential varying continuously from one region to the other; (2) the absence of a central line dividing the distribution into 2 symmetrical regions; (3) marked complexity of the individual equipotential loci; and (4) preponderance of potential difference on the anterior surface with the steepest gradient on the left side. This type of distribution of potential was entirely different from that of a surface doublet, so that it was impossible to define an angle value and the direction of an "axis line" employing the Einthoven formalism. In the absence of a surface doublet distribution the "zero line" representing the potential at the central terminal would be expected to and actually did vary from one instant to the next, since it cannot be at zero potential when a surface doublet distribution exists. The potential at the central terminal thus varied from one moment to the next during the QRS complex.