The combination method: a numerical technique for electrocardiographic calculations.

This paper presents a method for electrocardiographic and other bioelectric calculations combining the Green's function boundary integral technique with the finite element method. Both the boundary integral method and the finite element method have been used extensively in electrocardiography for calculating epicardial and torso potentials. The boundary integral method is well suited for finding potentials in regions of isotropic conductivity and is computationally efficient, requiring unknown potentials to be calculated on the bounding surfaces only. It also compares favorably in accuracy with the finite element method in those regions. The finite element method is used in solving for potentials in regions of anisotropic conductivity since no simplifying assumptions or transformations of anisotropic regions into isotropic regions before solution are required. Combining the two methods, using the boundary integral method in isotropic regions and the finite element method is anisotropic regions, allows the advantages of both methods to be exploited.