Effects of material properties and geometry on electrocardiographic forward simulations

This paper investigates the effect on torso potentials of changes in the ma terial properties of the torso volume conductor and changes in the relative geometry of the heart and torso. The investigations are performed using a number of forward simulations with a high-order coupled finite element/boun dary clement torso model. This torso model contains descriptions of the epi cardium, lungs, skeletal muscle (with a continuously varying fiber field) a nd subcutaneous fat. The number of nodes, elements and solution degrees-of- freedom used in the computational torso model are considerably smaller than previous torso models of similar complexity. The successful forward simula tions in this paper hence demonstrate the use of the high-order coupled app roach with realistic problems. The results of the torso simulations show th at the torso inhomogeneities do affect the torso potentials but do not affe ct the distribution or pattern of the torso potentials. The inhomogeneities considered are found to have a varying, but important, effect on the torso potentials. The effect of the subcutaneous fat is found to be more importa nt and the effect of the skeletal muscle is found to be less important than previous reports in the literature. The results also show that the relativ e geometry of the heart and torso is very important in determining the tors o potential magnitudes and distributions. (C) 2000 Biomedical Engineering S ociety. [S0090-6964(00)00407-0].