Figure 5.

Single premature impulses propagate through a structural heterogeneity when initiated far (5 mm away) from the heterogeneity. (A) Changes in I_Na current peak for single premature impulses, with different coupling intervals (S1S2), as the impulses propagate away from the stimulation site (x = 0 mm), in a preparation with a structural heterogeneity with average cell-to-cell coupling Gj = 0.41 μS in the proximal side and Gj = 4.95 μS in the distal side. The dashed vertical line indicates the location of the heterogeneity. (B) Action potentials calculated in the proximal side (2.5 mm from the border), at the border and in the distal side (2.5 mm from the border). Horizontal dashed line indicates a transmembrane potential of 0 mV. The dashed plot (S1S2 = 198 ms) is the shortest coupling that resulted in a propagated response. Size of the preparation: 10 × 2.5 mm (proximal side: 5 mm; distal side: 5 mm). Note that all single premature impulses propagate through the structural heterogeneity.