(46e) Study of Mechano-Electric Feedback On Cardiac Wave Propagation

Electrical alternans is a physiological phenomenon that is a beat-to-beat oscillation (alternation) of the cardiac Action Potential Duration (APD). Alternans have been shown to be a precursor to arrhythmias (Makarov L et al., 2010) and sudden cardiac death (SCD), which is the most common cause of death in the industrialized world. The presence of electrical alternans induces, through the mechanism of the excitation-contraction coupling (ECC), an alternation in the heart muscle contractile activity. Contraction of cardiac tissue also affects the process of cardiac electric wave propagation through the mechanism of so called mechano-electrical feedback (MEF) (Kiseleva I et al.,2000). The study of mechano-electrical feedback is an important direction of research in current cardiac electrophysiology.

A valuable method to study mechano-electrical feedback is mathematical modeling allowing the study of the coupled mechanical and electrical activity of the heart tissue. In our study, we use the Nash-Panfilov (NP) model (Nash and Panfilov, 2004), which describes electro-mechanical coupling in a 3D isotropic cardiac tissue at the most basic level. The Mooney-Rivlin material response is used to describe passive mechanical properties of the cardiac tissue. The coupled model includes an additional variable to represent the active stress which is responsible for mechanical deformation and is coupled to the stress equilibrium equations (Nash and Panfilov, 2004; Alvarez-Lacalle and Echebarria, 2009). The active and passive stress components are linearly superimposed to define the total state of stress in the tissue.

In this work, numerical examples are provided to illustrate the effects of mechanical deformation (perturbation) on wave propagation. This will serve to demonstrate that a significant contribution to the physiological and contractile tissue features is linked through the tissue mechanics as an underlying mechanism through the mechano-electric feedback. In addition, we will explore the possibility of cardiac alternans annihilation by applied mechanical perturbation.

References:

Makarov L, KomoliatovaV. Microvolt T-Wave Alternans during Holter Monitoring in Children and Adolescents. Annals of Noninvasive Electrocardiology15(2):138–144, 2010

Kiseleva I,Kamkin A, Wagner KD, Theres H, Ladhoff A, Scholz H, Gunther J, Lab MJ, Echebarria B. Mechano-electric feedback after left ventricular infarction in rats. Cardiovascular research: 45,370 – 378, 2000.

Nash M P, Panfilov A V. Electromechanical model of excitable tissue to study re-entrant cardiac arrhythmias. Prog. Biophys. Mol. Biol. 85, 501–522, 2004.

Alvarez-Lacalle E, Echebarria B. Global coupling in excitable media provides a simplified description of mechanoelectrical feedback in cardiac tissue. Phys review E, 79, 031921, 2009.