Theoretical Evaluation of the McFee and Frank Vectorcardiographic Lead Systems Using a Numerical Inhomogeneous Torso Model

This paper investigates the accuracy of the McFee and Frank vectorcardiographic (VCG) lead systems via numerical simulation. A 23 dipole heart model is used as the source. Unit dipoles are placed at each source dipole location and potentials are calculated at the appropriate vectorcardiographic electrode sites on the surface of a numerical inhomogeneous torso model comprising lungs, intraventricular blood masses, and an anisotropic-conductivity skeletal muscle layer. These potentials enable one to calculate the lead vectors relating a given source dipole to the voltage measured in a particular vectorcardiographic lead. Quantitative accuracy measures are utilized to compare lead vectors for the two vectorcardiographic systems. It was found that the McFee system is the superior if the blood masses are not included, but that this superiority is practically neutralized upon their inclusion. The McFee system is also the more accurate as regards uniformity of sensitivity in the X, Y, and Z directions.