Speaker: Fyodor A. Syomin, associate scientist of Center of Mathematical Modelling in Biomedicine, Russian University of Friendship
Topic: Electromechanical model of cardiac muscle tissue with mechano-electrical feedback
Annotation: Many heart diseases are associated with arrhythmias of various nature. Often arrhythmias can be initiated not only by disorders of the conductive properties of cardiac muscle, myocardium, in the wall of the heart chambers but also by the local disorders of its mechanical characteristics. Experimental data and clinical practice data demonstrate the presence of complex interrelationships between the processes of electrical activation of the myocardium and its mechanical contraction. The set of mechanisms by which the muscle electrical activation causes its contraction is called electromechanical coupling. In addition to such a direct influence of the electrical processes on the mechanics, there is inverse mechano-electrical feedback: the influence of the stress-strain state of the myocardium on the propagation velocity of the electric excitation wave. This feedback includes both indirect dependence, through the influence of the strain of a myocardial cell, cardiomyocyte, on the kinetics of intracellular ionic calcium currents, and the direct influence of macroscopic deformations on the conductive properties of cardiac muscle tissue.
For a deeper understanding of the causes of arrhythmias formation and conditions of their persistence, as well as for the development of accurate personalized models that could be applied in medical practice, a detailed model of myocardial electromechanics is needed. Such a model should take into account the above-mentioned interconnections of processes of various nature, and, if possible, be quite simple from a computational point of view. We present a prototype of the electromechanical model of the myocardium, in which the description of the electrical activation of the cardiac muscle by a simple Aliev-Panfilov model is coupled with a new model of myocardial mechanics developed by the group of the report author. The simulation results for the appearance and propagation of spiral waves of the action potential in deformable myocardium are shown. The effects of mechano-electrical feedback taken into account and introduced at the levels of the cell and tissue are demonstrated.