In this paper, we have defined an optimization problem allowing to directly find the shape of the cardiac wave of some ionic models. This allowed us to compare some of these ionic models via a parameter identification problem instead of comparing them directly by plotting the graphs for given values of the parameters. Compared to the empirical methods used to adjust one or two parameters at a time encountered in electrophysiology, we believe that our parameter identification approach is reliable and able to simultaneously identify four to eleven parameters of an ionic model. Using this approach, we adjusted the parameters of the Mitchell-Schaeffer and Aliev-Panfilov models to recover the shape of the action potential obtained experimentally by fluorescence.