Torso coupling techniques for the forward problem of electrocardiography

The calculation of body surface potentials from a known cardiac source is traditionally formulated in terms of a two step process. The first step involves the generation of some form of equivalent cardiac source (typically dipole based) at a resolution significantly lower than that of a continuum cell. The second then places that source into a volume conductor within which the potential fields are calculated. This approach does not properly capture the feedback between the torso and the extracellular potential field. Presented here are the details of two new methods which calculate continuous potential fields throughout the torso that are the direct result of cardiac cellular electrical activity. These new methods are termed the Boundary Iteration Method and the Direct Assembly Method. While these two methods return essentially identical answers, there is a definite tradeoff between computational speed and memory overhead with the direct assembly method proving faster but requiring significantly more memory. Examples are given that demonstrate the convergence and accuracy of these methods in an idealized coupled torso system. These techniques are then applied to an anatomically based model of a slice through a human male torso. © 2002 Biomedical Engineering Society. PAC2002: 8719Nn, 8717-d, 8719Hh