svFSI: A Multiphysics Package for Integrated Cardiac Modeling

Abstract

Heart disease is the number one cause of death in the US (Xu et al., 2020). Many efforts have been devoted to studying its progression, diagnosis, and treatment. During the past decade, computational modeling has made significant inroads into the research of heart disease. The heart is inherently a multiphysics system that includes electrophysiology, tissue mechanics, and blood dynamics. Its normal function starts with the propagation of electrical signals that trigger the active contraction of the heart muscle to pump blood into the circulatory system. Rooted in fundamental laws of physics such as the balance of mass, momentum, and energy, computational modeling has been instrumental in studying cardiac physiology such as left ventricular function (Mittal et al., 2015), cardiac arrhythmia (Trayanova, 2011), and blood flow in the cardiovascular system (Arzani & Shadden, 2018; Grande Gutiérrez et al., 2021). svFSI is the first open source software that specializes in enabling coupled electro-mechano-hemodynamic simulations of the heart. Statement of need Accompanying the growing popularity of studying cardiac physiology with computational modeling, many open source software tools that specialize in modeling one or two aspects of the multiphysics process in the heart have been developed. For example, SimVascular (Updegrove et al., 2017) enables patient-specific blood flow modeling by providing a complete pipeline from medical image segmentation to simulation results. FEBio (Maas et al., 2012) specializes in modeling large-deformation structure mechanics in biophysics with fluid-structure interaction (FSI) capability as well. openCARP (Plank et al., 2021) focuses on modeling cardiac electrophysiology. There are other general-purpose open source software such as LifeV (Bertagna et al., 2017) and FEniCS (Logg et al., 2012), that can be flexibly adapted to simulate different physics in the heart, but significant development effort may be required for this purpose. Recently, Quarteroni et al. have also been developing an open source simulator for the cardiac function, and the fiber generation module (Africa et al., 2022) and electromechanics (Fedele et al., 2022) have been announced so far. svFSI is a new multiphysics finite element solver designed specifically for computational modeling of integrative heart dynamics. As the next generation finite element solver for the SimVascular software, svFSI is capable of modeling hemodynamics, performing large-deformation FSI to capture the motion of cardiac chambers and their interaction with the blood flow, and simulating the complex excitation-contraction coupling between the intracellular ion-exchange processes and tissue contraction. To suit the diverse needs of users, our team Zhu et al. (2022). svFSI: A Multiphysics Package for Integrated Cardiac Modeling. Journal of Open Source Software, 7 (78), 4118. https: //doi.org/10.21105/joss.04118.