Active contraction-integrated FSI: Numerical modeling of cardiac pumping

Abstract

This study develops a fluid–structure interaction (FSI) model of the cardiovascular system to simulate the heart’s pumping action and hemodynamics. The model integrates an active contraction mechanism to accurately represent cardiac function. To capture the passive mechanical properties of the heart muscle, an anisotropic hyperelastic model is used. The active contraction is described by incorporating force–length and force–velocity relationships, which are calibrated with experimental data, alongside a time-dependent activation function based on cellular action potentials. The Arbitrary Lagrangian–Eulerian (ALE) method governs the FSI between the blood and the deforming ventricle and aorta. An immersed boundary method is employed to manage the FSI boundary and prevent numerical issues like leakage, while physiological pressure conditions are applied at the outlets. The model’s predictions for aortic flow, pressure, and left ventricular contraction were validated against existing experimental data. The results show the model successfully predicts cardiac pumping and contractile behavior. This demonstrates its potential for future applications in simulating heart diseases and studying cardiovascular trauma.