CV depends on Na ⁺ channel distribution, cleft width, and gap junctional coupling. CV is shown as a function of cleft width (w) for (A–(A-G) G) different Na⁺ channel distributions and gap junction conductance g_gap. For polarized distributions, narrow cleft slows conduction for high g_gap and enhanced conduction for low g_gap. The physiological distribution (mix/homogeneous-polarized) exhibits the greatest sensitivity to cleft width. Parameters: f_Na = 0.7.