Mechano-electric feedback effects in a ventricular myocyte model subjected to dynamic changes in mechanical load

The effect of mechano-electric feedback (MEF) on myocyte´s action potential (AP) has been largely studied considering constant stretches. The present study examined the role of MEF utilizing a model built by integrating mathematical descriptions of cardiac myocyte´s electrical activity, contraction and MEF. This model simulates the four phases of the cardiac cycle as a sequence of isometric and isotonic contractions/relaxations, i.e. ideal work loops (WLs). Intracellular Ca²⁺ controls contraction and sarcomere length is used as input to MEF, that in turn affects the AP through the action of stretch-modulated currents. Simulations were conducted to investigate the role of MEF in modulating electrical activity during WL for different length preloads and force afterloads. Results were in agreement with experimental WL and MEF studies. Moreover, on the base of simulation results, it can be asserted that the generation of arrhythmogenic phenomena could arise when the strength of the MEF is increased, as under heavy myocardium stress conditions.