A patient-specific FSI model of congenital heart disease

Numerical modeling of cardiac biomechanics and hemodynamics offers a powerful framework for understanding disease mechanisms in congenital heart disease (CHD) and informing personalized treatment strategies. Hemodynamics are particularly important in CHD cases, where structural abnormalities can cause severely disturbed blood flow. We present a patient-specific, fluid-structure interaction (FSI) model of the heart with a ventricular septal defect (VSD). The numerical model leverages the arbitrary Lagrangian–Eulerian (ALE) formulation to couple blood flow with myocardial mechanics, incorporating a Holzapfel-Ogden material law and an active stress formulation. Cardiac valves are represented using resistive immersed surfaces (RIS), allowing efficient modeling of valve dynamics. Additionally, the FSI heart model is coupled to a closed-loop lumped-parameter network (LPN) representing systemic and pulmonary circulations, which provides physiological boundary conditions on the heart and captures interactions between cardiac function and circulatory dynamics. Model parameters are personalized to routine clinical data (electrocardiogram, cuff blood pressures, time-resolved CT imaging) using a multistep strategy, following our prior work. By resolving fluid-solid coupling in a patient-specific CHD heart, the model enables mechanistic investigation of altered hemodynamics and offers a tool for evaluating surgical interventions.