Pranav Bhagirath

151 Computing volume potentials for noninvasive imaging of cardiac excitation INTRODUCTION Non-invasive imaging of cardiac excitation using recorded body surface potentials (BSP) and mathematical inverse procedures is an active field of research that has yielded some clinical applications [1-4]. In an inverse procedure, local epicardial potentials or myocardial activation times are computed from recorded BSP. In contrast, a forward procedure estimates BSP from potentials measured on the surface of the heart [5-6]. The Boundary Element Method (BEM) has been favoured for electrocardiographic forward procedures due to enhanced computational efficiency and reduced modelling effort [7-9]. In contrast to the BEM, which yields potential information on predefined surfaces, the Finite Element Method (FEM) provides body volume potentials (BVP) ( figure 1 ) [10]. BEM FEM LL RL H Thorax LL RL H Thorax Figure 1. The Boundary Element Method (BEM) yields potential information on predefined surfaces only. Hence, no information on the areas between the compartments can be derived when using the BEM. The Finite Element Method (FEM) on the contrary, provides body volume potentials (BVP). Volume potentials can be computed as well using the BEM, by increasing the number of model compartments. However, the FEM is typically more efficient, especially when the number of model compartments is high or when anisotropic conductivity is modelled. (RL right lung; LL left lung; H heart; L liver) Utilizing knowledge on the spatial potential field may lead to improved insight in the potential distribution throughout the thorax. Although potentials can be computed everywhere in a volume as well using the BEM by creating multiple surfaces inside the