Control of Cardiac Alternans in a Realistic Electromechanical Model of Cardiac Tissue

Electrical alternans is a physiological phenomenon manifested as beat-to-beat oscillation (electric wave width alternation) of the cardiac action potential duration. Alternans has been shown to be a precursor to arrhythmias and sudden cardiac death, which is the most common cause of death in the industrialized world. The control of alternans has been explored in many studies in the literature. However, the majority of the existing control algorithms succeeded in suppressing alternans only in small pieces of cardiac muscle. To our knowledge, all the control algorithms are electric-based realization and have not considered mechanical properties of cardiac tissue, despite the fact that mechanical deformation is shown to influence the electrical activity of the heart tissue, and consequently the cardiac alternans. In a previous work, we presented a novel mechanical perturbation algorithm to control alternans. The proposed control algorithm succeeds to suppress the alternans in relevantly sized cardiac tissues. However, only a simplified mathematical model has been used for the numerical simulation and a more realistic model should be used to investigate the control of alternans which is the goal of this study. In this work, we will explore the feasibility of suppressing cardiac alternans in a realistic model by using the mechanical perturbation strategy.  The electrical activity is represented by the Luo-Rudy model and the mechanical activity is represented by an active contractile tension model and the Mooney-Rivlin passive elasticity model. Numerical simulations are used to illustrate the feasibility and the effects of the proposed algorithms in suppressing cardiac alternans.