Figure 4. Physiological behaviour in 1D models when there is a gradient both in cell type (from central-type to peripheral-type) and in electrical coupling (g j from 25 nS to 4,000 nS).
A, Kurata-Lindblad 1D model (x 1 = 1.2 mm, x 2 = 1.28 mm). B, Zhang-Oxsoft 1D model (x 1 = 1.0 mm, x 2 = 1.32 mm). In both models, spontaneous activity originated in the centre of the SAN and the SAN drove the atrial muscle. Left, membrane potential of all cells. Right, C m (top), g j (second panel), activation and repolarization time (open and filled symbols, respectively; third panel) and safety factor (bottom) along length of model. Arrow, leading pacemaker site.