Effects of cardiac anisotropy on modeling transvenous defibrillation in the human thorax

The objective of this study is to determine the effects of cardiac tissue anisotropy on transvenous defibrillation fields in a human torso model. The study is implemented with a physiologically realistic 3-D finite element model of the human thorax. The model computes potential and potential gradient distributions within the heart from a knowledge of defibrillation shock strength, defibrillation electrode location, and the relative conductivities of the interior thorax. Coil electrodes were placed in the right ventricular cavity and the superior vena cava. Results are compared between a model with an isotropic myocardium and a model with an anisotropic myocardium. Comparison of the potential and potential gradient distributions within the myocardium between the isotropic and anisotropic models yielded root mean square errors of 4.9% and 19.%, respectively, and correlation coefficients of 0.999 and 0.981, respectively. These results indicate that cardiac anisotropy and fiber orientation do not significantly affect transvenous defibrillation fields.