A study on the effects of mechanoelectric feedback and mechanical perturbation approach on the electrical properties using a bidomain model of cardiac tissue
Electrical alternations in cardiac action potential duration have been shown to be a precursor to arrhythmias and sudden cardiac death (Makarov L et al., 2010). Through the mechanism of excitation-contraction coupling, the presence of electrical alternans induces alternations in the heart muscle contractile activity. Also, contraction of cardiac tissue affects the process of cardiac electric wave propagation through the mechanism of so-called mechanoelectrical feedback (MEF). Electrical excitation and contraction of cardiac tissue can be linked by an electromechanical model such as the Nash-Panfilov (NP) model (Nash M P et al.,2004; Panfilov A V et al.,2005).
The electrical activity of the heart is usually modelled using the bidomain or monodomain equations. The bidomain model (Keener J et al.,2008) consists of a system of coupled parabolic and elliptic PDEs for two potentials in the cardiac muscle, coupled with a nonlinear system of ODEs describing the ionic currents flowing across the cardiac membrane. This model, which is computationally very expensive, is more accurate description of macroscopic electrical activity of the heart than the monodomain model and it is also the preferred model for simulating cardiac excitation, such as during cardiac pacing, when the main emphasis is how a voltage develops across the membrane. The hyperelastic Mooney-Rivlin (MR) material model has been used to model the nonlinear mechanical behavior of the myocardium (Nash M P et al.,2004; Panfilov A V et al.,2005).
In this work a strongly coupled electromechanical model, that account for the effects of electrical activity on the cardiac mechanics and the effect of mechanical deformation on electrical properties in a bidomain setting, will be utilized to study the basic electrical and mechanical properties of the heart, including action potential propagation, defibrillation, electrocardiographic (ECG) measurement, and mechanical stretch and shortening. In addition the effects of mechanical deformation via MEF and mechanical perturbation approach (Yapari et al., 2014) on wave propagation will be illustrated. This will help to explore the possibility of suppressing cardiac alternans by applied mechanical perturbation approach.
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