The muscle cells (cardiomyocytes) that make up all of the heart muscle contract in a repetitive, organized and adapted way in order to ensure the final function of circulatory support. The coordination of the contractile function is ensured thanks to the syncitium structure of the cardiac tissue which allows the propagation of the electrical activity from one cardiac cell to another. This electrical activity translates into an action potential (AP) which represents the result of a cascade of ion transfers (entry of Na+ and Ca++ ions, exit of K+ ions), largely depending on the variations in permeability of the sarcolemma and succeeding from the diastolic potential. The latter, located between -80 and -90 mV, depends on the characteristics of the sarcolemma which, at rest, is almost exclusively permeable to K+ , and on the variations in ionic concentrations (Na+ and K+ ) on either side of this membrane. However, in diastole, the sarcolemma is slightly permeable to Na+ and the concentration gradients are maintained thanks to active transport ensured by an electrogenic ATP-dependent Na+ /K+ membrane pump.