Effect of the Mitral Valve on the Intra Ventricular Hemodynamics.

To evaluate the impact of intracardiac flow features on the efficiency of the transfer of the myocardium's contractile mechanical power into blood flow hydraulic power. A time evolving 3D mesh corresponding to a patient-specific left heart was generated from medical images to obtain the intracardiac hemodynamics via computational fluid dynamics. A parametric model of the mitral valve is used to investigate the influence of its opening area and orientation on the hemodynamics. The complete ventricular kinetic energy balance equation is established, and its terms are quantified to characterize the fraction of contractile power transferred to the blood flow. The simulations indicate that the influence of MV on blood flow pattern and vortices is significant. Dissipation and TKE in the left ventricle have a strong dependence on the MV model. Their values are higher when mimicking pathologies such as calcification of the MV (resulting in a smaller opening area), and reduced when the opening area is larger. While the orientation of the MV opening exerts a considerable impact on flow patterns, its effect on dissipation and TKE is less pronounced. For all the cases considered, the amount of energy dissipated over one cardiac cycle is a small fraction (1%-2%) of the energy at play to pump blood towards the aorta. In absence of valve leakage, the energy dissipated by viscous effect is marginal in all the healthy and pathological cases considered.