The zero potential and Wilson's central terminal in electrocardiography

Abstract

For unipolar electrocardiography, a zero reference electrode is necessary. The zero potential is usually considered as that at infinity but not well understood for a finite conductor. In practice, Wilson's central terminal has been utilized, as a zero equivalent, with remarkable clinical success. The grade of approximation has, however, not been established. In this paper, we discuss related topics including a review of older literature, the definition of zero potential and the method for obtaining the zero potential from the measurements on the body surface. With this method, the potential of Wilson's electrode with respect to that at infinity can be calculated. Our previous calculation in 60 clinical cases showed the time course of the absolute voltage of Wilson's electrode, which is nearly parallel with the body surface potential.