A non-conforming-in-space numerical framework for realistic cardiac electrophysiological outputs

Computer -based simulations of non-invasive cardiac electrophysiological outputs, such as electrocardiograms and body surface potential maps, usually entail severe computational costs due to the need to capture fine -scale processes and to the complexity of the heart -torso morphology. In this work, we model cardiac electrical outputs by employing a coupled model consisting of a reaction -diffusion model - either the bidomain model or the most efficient pseudobidomain model - on the heart, and an elliptic model in the torso. We then solve the coupled problem with a segregated and staggered in -time numerical scheme, that allows for independent and infrequent solutions in the torso region. To further reduce the computational load, we propose to rely on an interpolation method at the interface between the heart and torso domains, enabling the use of non -conforming meshes, and the consequent application of our numerical framework to realistic cardiac and torso geometries. The reliability and efficiency of the proposed scheme are tested against the corresponding state-of-the-art bidomain-torso model. Furthermore, we explore the impact of torso spatial discretization and geometrical non -conformity on the model solution and the corresponding clinical outputs. The investigation of the interface interpolation method provides insights on the influence of both the torso spatial discretization and the geometrical non -conformity on the simulation results, as well as on their clinical relevance.