Fig. 1.

A: schematic of the inhomogeneous 1 × 1-cm microstructural tissue model that includes a 0.4 × 0.4-cm poorly coupled central region [where g_j(PC) is the gap junction conductance (g_j) in this region]. The sites of recording electrodes are indicated with white circles. The electrograms recorded for wavefronts propagating along the longitudinal and transverse axes in control tissue (see Fig. 9) were taken at the black recording electrode. B–F: magnified views of the transition region between the well-coupled region [where g_j(WC) is g_j in this region] and poorly coupled region for the regular brick wall model (B), the combination uniform-brick wall model with a single brick wall section (C), the random brick wall model (D), the random model with cell jutting (E), and the random model with fibrosis (F). The poorly coupled cells [g_j(PC) = 0.10–0.004 μS] are outlined in dark gray, the well-coupled cells are outlined in light gray, and the lateral decoupling caused by fibrosis is indicated with bold, red lines. The stimulus site is indicated with a current source symbol.