Theoretic Analysis of the Influence of Heart-Dipole Eccentricity on Limb Leads, Wilson Central-Terminal Voltage and the Frontal-Plane Vectorcardiogram

Abstract

This is a theoretic investigation of the influence of the position of a current dipole on the electric potential produced at the boundary of a homogeneous conducting sphere. Thirty different eccentric dipole positions are selected within the sphere to bear analogy to locations of the equivalent dipole of the human heart within the chest, and boundary-potential calculations are made from points selected to bear analogy with body-surface points utilized in limb leads, Wilson centralterminal and frontal-plane electrocardiography. The point of view taken differs completely from the scalene-triangle geometric representation of eccentricity; instead, an equilateral triangle is used in conjunction with assigned strength and orientation time-variations for the eccentric dipole. It is concluded that if electrocardiography were subject to no other limitation of the application of field analysis, eccentricity of dipole position alone can produce very significant deviations between the manifest heart vector and the true heart vector in both direction and magnitude. The dependence of the Wilson central-terminal voltage on dipole eccentricity is likewise appreciable and of the same order of magnitude as reported by several experimenters; however, the effects of eccentricity on the Wilson central-terminal voltage are generally less pronounced than on the manifest heart vector.