Understanding the interaction between the valves and walls of the heart is
important in assessing and subsequently treating heart dysfunction. With
advancements in cardiac imaging, nonlinear mechanics and computational
techniques, it is now possible to explore the mechanics of valve-heart
interactions using anatomically and physiologically realistic models. This
study presents an integrated model of the mitral valve (MV) coupled to the left
ventricle (LV), with the geometry derived from in vivo clinical magnetic
resonance images. Numerical simulations using this coupled MV-LV model are
developed using an immersed boundary/finite element method. The model
incorporates detailed valvular features, left ventricular contraction,
nonlinear soft tissue mechanics, and fluid-mediated interactions between the MV
and LV wall. We use the model to simulate the cardiac function from diastole to
systole, and investigate how myocardial active relaxation function affects the
LV pump function. The results of the new model agree with in vivo measurements,
and demonstrate that the diastolic filling pressure increases significantly
with impaired myocardial active relaxation to maintain the normal cardiac
output. The coupled model has the potential to advance fundamental knowledge of
mechanisms underlying MV-LV interaction, and help in risk stratification and
optimization of therapies for heart diseases.Comment: 25 pages, 6 figure
