Simulating the excitation propagation in mechano-electrical models of myocardial cells

A three dimensional model of a myocardial area is presented, which allows the simulation of electrical excitation propagation under the influence of stretch. The model is based on a modified Noble-Varghese-Kohl-Noble model of a ventricular cell. The simulation of the propagation of electrical excitation via intercellular current flow is performed by the traditional and an extended bidomain model. Simulations with the models show, that the influence of the stretch dependent electrophysiological model is starting at a stretch larger than 1 leading to an approximately exponential progression of the conduction velocity in the selected range of stretch. This effect results from the raise of the resting potential by stretch with the consequence that a smaller and therefore faster deliverable amount of electrical charge is sufficient to initiate an excitation. Comparisions of the simulations with published measurements are carried out.