Propagation wavefronts in two-dimensional topologies of cardiac cell networks

We present a computer model, implemented on a Cray-2 supercomputer, to explore the role of the discontinuous, nonuniform, and anisotropic cellular structure of cardiac tissue on normal propagation patterns. For this study, we hold cell shape constant and evaluate planar propagation wavefronts oriented longitudinally and transversely to the cell axis for two different tissue topologies-rectangular and brick-like-and for different degrees of transverse coupling strengths between cells. Nonuniformity is introduced into the model via spatial dispersions of coupling strengths. Even under severe conditions of uncoupling, both topologies show remarkable abilities in maintaining a uniformly planar wavefront. Thus, our simulations suggest that cardiac cell networks are very robust in their abilities to equilibrate electrical spatial inhomogeneities, even in the face of significant structural and coupling inhomogeneities.