Visualization of wave propagation through a 3D strand of myocardium

The authors present recent results obtained from simulating the action potential generation and propagation through a thin 3-D cylindrical heart muscle bundle. These results represent the first step towards obtaining a more accurate understanding of wave propagation properties through striated muscles. Using a 3-D computational grid of 32×32×128 cells, a single muscle bundle was modeled. The individual fibers and inter-fiber matter making up the bundle were treated homogeneously. Using a modified FitzHugh-Nagumo equation called the Epsilon-4 model, the authors obtained the relationship of propagation speed as a function of cross-sectional depth. The variations in speed that were observed can be explained in terms of the different wave curvatures arising from different types of boundary conditions and the geometry of the pathway. From these observations, the authors construct experiments where unidirectional blocks can occur in geometries with low excitability and no flux borders