Simulating Cardiac Fluid Dynamics in the Human Heart
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Cardiac fluid dynamics fundamentally involves interactions between complex blood flows and the structural deformations of the muscular heart walls and the thin, flexible valve leaflets. There has been longstanding scientific, engineering, and medical interest in creating mathematical models of the heart that capture, explain, and predict these fluid-structure interactions. However, existing models that account for interactions among the blood, the actively contracting myocardium, and the cardiac valves are limited in their abilities to predict valve performance, resolve fine-scale flow features, or use realistic descriptions of tissue biomechanics. Here we introduce and benchmark a comprehensive mathematical model of cardiac fluid dynamics in the human heart. Our model accounts for all major cardiac structures and is calibrated using tensile tests of human tissue specimens to reflect the influences of myocyte and collagen fiber alignment. It includes biomechanically detailed three-dimensional descriptions of all four cardiac valves, including the chordae tendineae and papillary muscles. We demonstrate that the model generates physiologic dynamics, including realistic pressure-volume loops that automatically capture isovolumetric contraction and relaxation, and predicts fine-scale flow features. Critically, none of these outputs are prescribed; instead, they emerge from interactions within the integrative model. Such models can serve as tools for predicting the impacts of medical devices or clinical interventions, particularly those that fundamentally involve the heart valves. They also can serve as platforms for mechanistic studies of cardiac pathophysiology and dysfunction, including congenital defects, cardiomyopathies, and heart failure, that are difficult or impossible to perform in patients.
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