Computer-based simulations of non-invasive cardiac electrical outputs, such as electrocardiograms and body surface potential maps, usually entail severe computational costs due to the need of capturing 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 pseudo-bidomain 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 solution in the torso region. To further reduce the computational load, main novelty of this work is in introduction of an interpolation method at the interface between the heart and torso domains, enabling the use of non-conforming meshes, and the numerical framework application to realistic cardiac and torso geometries. The reliability and efficiency of the proposed scheme is 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 into the influence of torso spatial discretization and of the geometrical non-conformity on the simulation results and their clinical relevance.

翻译：基于计算机的无创心电输出模拟（如心电图和体表电位图）通常需要极高的计算成本，原因在于需要捕捉精细尺度过程以及心脏-躯干形态的复杂性。本研究采用耦合模型对心电输出进行建模：心脏部分采用反应扩散模型（包括双域模型或更高效的伪双域模型），躯干部分采用椭圆模型。我们采用分离式时间交错数值格式求解该耦合问题，该格式允许对躯干区域进行独立且低频次的求解。为进一步降低计算负载，本文主要创新在于引入心脏与躯干域交界面的插值方法，使得非协调网格的使用成为可能，并将该数值框架应用于真实心脏与躯干几何形态。通过与当前先进的双域-躯干模型对比，验证了所提方案的可靠性与效率。此外，我们探讨了躯干空间离散与几何非协调性对模型解及其对应临床输出的影响。对交界面插值方法的研究揭示了躯干空间离散与几何非协调性对模拟结果及临床相关性的影响规律。