Reducing mesh size for finite element modeling of transvenous defibrillation

The objective of this study is to determine if transvenous defibrillation simulations can be simplified by reducing the size of the volume conductor model. The study is implemented with a physiologically realistic 3-D finite element model of the human thorax. The model computes potential distributions within the heart from a knowledge of defibrillation shock strength, defibrillation electrode location, and the relative conductivities of the interior thorax. Results are compared between a model of the entire torso and a model consisting only of the heart surrounded by a spherical shell. Comparison of the potential distributions within the heart between the two models yielded a root mean square error of 13.696 and a correlation coefficient of 0.995. For the finite element solution, storage requirements were decreased by a factor of 4 and computational time was reduced by a factor of 15. These results indicate that for transvenous defibrillation simulations the size of the model can be greatly reduced by excluding the interior structures of the torso external to the heart. In addition, the results suggests that interior structures such as the lungs may not affect the potential distributions within the heart during transvenous defibrillation.