We develop a novel large-scale kinematic model for animating the left ventricle (LV) wall and use this model to drive the fluid-structure interaction (FSI) between the ensuing blood flow and a mechanical heart valve prosthesis implanted in the aortic position of an anatomic LV/aorta configuration. The kinematic model is of lumped type and employs a cell-based, FitzHugh-Nagumo framework to simulate the motion of the LV wall in response to an excitation wavefront propagating along the heart wall. The emerging large-scale LV wall motion exhibits complex contractile mechanisms that include contraction (twist) and expansion (untwist). The kinematic model is shown to yield global LV motion parameters that are well within the physiologic range throughout the cardiac cycle. The FSI between the leaflets of the mechanical heart valve and the blood flow driven by the dynamic LV wall motion and mitral inflow is simulated using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, 2007; Borazjani et al., 2008) [1,2] implemented in conjunction with a domain decomposition approach. The computed results show that the simulated flow patterns are in good qualitative agreement with in vivo observations. The simulations also reveal complex kinematics of the valve leaflets, thus, underscoring the need for patient-specific simulations of heart valve prosthesis and other cardiac devices.
Bibliographical noteFunding Information:
This work was supported by NIH Grant RO1-HL-07262 and the Minnesota Supercomputing Institute. We would like to thank Professor Ajit Yoganathan and his associates for providing us the anatomic geometry of the left ventricle. We also acknowledge the help of Professor Iman Borazjani in implementing the domain decomposition aspects of the numerical method. The first author was supported partially by a fellowship from Vietnam Education Foundation.
- Bi-leaflet mechanical heart valve
- Cardiac electrophysiology
- FitzHugh-Nagumo model
- Fluid-structure interaction
- Left heart hemodynamics
- Patient-specific modeling