Electrical excitation of the human heart: a comparison of electrical source distributions in models of different spatial resolution

Subject of this study is the simulation of the electrical excitation propagation based on anatomical and physiological models of the human heart. An anatomical model of high spatial resolution was created applying advanced strategies of 3D digital image processing to the Visible Human data set provided by the National Library of Medicine, Bethesda, Maryland (USA). It comprises 42 classes of tissue including the cardiac conduction system. In addition, the fibre orientation of the cardiac and skeletal muscle was determined end assigned to each voxel of the model. Source distributions were calculated based on a 3D bidomain model applying a cellular automaton to these models to simulate the excitation process. The anisotropic behaviour of the cardiac muscle with regard to electrical conductivity and propagation velocity was taken into account as well as physiological properties of the cardiac tissue. Source distributions of differently scaled models were compared.