Resumen: Constant conductances are often assumed when model-
ing cardiac tissue. However experimental evidences have
shown that gap junctions (GJ) actually connect adjacent
cardiac myocytes. These GJ are complex proteins of the
connexin family (Cx40; Cx43; Cx45 are the most common
in human). These GJ modify the conductances between
cardiac cell through a dynamical process. The aim of this
study is to develop a bidomain model of the cardiac tis-
sue where the dynamics of the connexins is also included.
In particular we will compare the differences associated
with the use of a monodomain versus bidomain formula-
tion in inducing intra-cellular conductance variations. We
have found that the monodomain formulation gives con-
ductance variations a factor four to five larger with respect
to the bidomain formulation.