  In this paper, we find relations between the ionic parameters and the
diffusion parameters which are sufficient to ensure the existence of a periodic
solution for a well-known monodomain model in a weak sense. We make use of the
method of approximation of Faedo-Galerkin to prove the existence of weak
periodic solutions of the monodomain model for the electrical activity of the
heart assuming that it is periodically activated in its boundaries. Actually,
this periodic solution has the same period of activation. Finally, we reflect
on how these ionic-diffusive relations are useful to explain the
pathophysiology of some rhythm disorders.
