Description

Heart disease is among the leading causes of death in the Western world; hence, a deeper understanding of cardiac functioning will provide important insights for engineers and clinicians in treating cardiac pathologies. However, the heart also offers a significant set of unique challenges due to its extraordinary complexity. In this respect, some recent efforts have been made to be able to model the multiphysics of the heart using LS-DYNA.

The model starts with electrophysiology (EP) which simulates the propagation of the cell transmembrane potential in the heart. This electrical potential triggers the onset of cardiac muscle contraction, which then results in the pumping of the blood to the various organs in the body. The EP/mechanical model can be coupled with a Fluid and Structure Interaction (FSI) model to not only study the clinically relevant blood flow parameters as well as valves or cardiac devices. 

Different propagation models, called “mono-domain” or “bi-domain”, which couple the diffusion of the potential along the walls of the heart with ionic equations describing the exchanges between the inner and the outer parts of the cells have been implemented. These models were first benchmarked against published results obtained from other EP research codes on a simple cuboid heart tissue model. Other simulations were then performed on more realistic geometries. Since the potential diffusion is highly orthotropic, with much larger diffusion coefficients along the fibers of the tissue than transversely, it is important to correctly model these fibers, which creates models with very large numbers of elements (several tens to hundreds of millions of elements). We thus implemented capabilities to be able to handle such large-scale models. In this section, some EP models will be presented along with some results.