Autonomous Electrical Activity Induced By Cardiac Tissue Deformation In A Thermo-Electro-Mechanical Background ⋆

In a healthy heart, the mechano-electric feedback (MEF) process acts as an intrinsic regulatory mechanism of the myocardium which allows the normal cardiac contraction by damping mechanical perturbations in order to generate a new healthy electromechanical situation. However, under certain conditions, the MEF can be a generator of dramatic arrhythmias by inducing local electrical depolarizations as a result of abnormal cardiac tissue deformations, via stretch-activated channels (SACs). Then, these perturbations can propagate in the whole heart and lead to global cardiac dysfunctions. In the present study, we examine the spatio-temporal behavior of the autonomous electrical activity induced by the MEF when the heart is subject to temperature variations. For instance, such a situation can occur during a therapeutic hypothermia. This technique is usually used to prevent neuronal injuries after a cardiac resuscitation. From this perspective, we introduce a one-dimensional time-dependent model containing all the key ingredients that allow accounting for excitation-contraction coupling, MEF and thermoelectric coupling. Our simulations show that an autonomous electrical activity can be induced by cardiac deformations, but only inside a certain temperature interval. In addition, in some cases, the autonomous electrical activity takes place in a periodic way like a pacemaker. We also highlight that some properties of the action potentials that are generated by the MEF, are significantly influenced by temperature. Moreover, in the situation where a pacemaker activity occurs, we also show that the period is heavily temperature-dependent.