Monodomain simulations of excitation and recovery in cardiac blocks with intramural heterogeneity

Large scale simulations of an anisotropic and heterogeneous cardiac model in three dimensional myocardial blocks are presented. The Monodomain tissue representation used includes orthotropic anisotropy, intramural fiber rotation and homogeneous or heterogeneous intramural Luo-Rudy I membrane ionic models. Simulations of the entire QT interval for epicardial and endocardial pacing show that the effect of intramural heterogeneity on the dispersion of the action potential duration is mostly discernible along the epi- endocardial direction, while in the orthogonal directions the dispersion patterns have the same qualitative features of the homogeneous model.