Numerical Modeling of the Work of the Left Ventricle of the Heart in the Circulatory System: The Effects of Changes in the Frequency of Contractions and Apical Myocardial Infarction

Abstract

We present a multiscale mathematical model of the pumping function of the left ventricle (LV) of the heart in the circulatory system. The properties of the LV myocardium were described with a new electromechanical model that combines models of the generation and propagation of action potential, electromechanical coupling, and mechanics, including passive and active mechanical stress and finite strain. The left ventricle was considered to be a thick-walled axisymmetric body with a realistic distribution of the muscle fibers within its wall. Blood flow in other heart chambers and blood vessels was represented by a lumped parameter model. We carried out numerical modeling of the effects of the heart rate, partial atrioventricular block, and apical LV infarction on the hemodynamics and geometry of the LV. The calculations showed that the model describes the observed responses of the LV pumping characteristics to these effects. The results allow one to understand how the cell-level peculiarities of the electromechanical coupling in cardiac muscle help the heart to maintain its pumping function in pathologies and to adjust it to the increasing needs during physical activity.