Influence of spatial resolution of impedance models on the solution of the forward problem in electrocardiography

This study deals with the forward problem in electrocardiography, which consists of calculation of the potential distribution in the human body due to cardiac sources. An important task is the selection of appropriate models, because their properties determine the quality of the solution of the forward problem. The property examined in this study is the spatial resolution of impedance models. The examination is carried out by analysis and comparison of computed body surface potential maps, which are calculated based on a set of models with different spatial resolution. The computation is performed numerically using the finite difference method. The implementation of the finite difference method allows the solving of large problems on workstations. The comparison showed an increase of potential differences with an decrease of spatial resolution due to wrong assignment of tissue to voxels, increasing discretisation error of the approximation by the finite difference method, and misplacement of boundary conditions. The largest differences can be found near to the location of the current and voltage sources