Dynamical effects of myocardial ischemia in anisotropic cardiac models in three dimensions

The interaction between the presence of severe myocardial ischemia
and the anisotropic structure of the cardiac muscle is here
investigated by means of numerical simulations of the anisotropic
Bidomain and Monodomain models. The Bidomain model is a degenerate
system of two parabolic reaction-diffusion equations that can be
rewritten as a parabolic-elliptic system, while the Monodomain
model consists of a single parabolic equation. Both models are
coupled with a systems of ordinary differential equations
related to the ionic currents flowing through the cellular
membrane. The resulting fully coupled model includes intramural
fiber rotation, orthotropic or axisymmetric anisotropy and
homogeneous intrinsic membrane properties, modeled by an
updated version of the Luo-Rudy membrane ionic model.
Features of the cardiac excitation, recovery sequences and the distribution of the action
potential duration elicited by a local stimulation are investigated in presence of
severe subendocardial ischemia. Some epicardial markers correlated
to the underlying subendocardial ischemic region are discussed.