Spiral waves with zero-, one-, and two-sided couplings:

<p>Pseudocolor plots of at time s in a simulation domain with cm, an MF composite at every site, with a myocyte M coupled via nS with one fibroblast F ( pF, nS, and mV) for (a) control case with only myocytes and no fibroblasts, (b) zero-sided coupling, (c) single-sided coupling with , and (d) double-sided coupling with and ; the white solid lines in plots (a), (b), (c), and (d) show the trajectories of the spiral tip for . <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0072950#pone.0072950.s006" target="_blank">Video S5</a> illustrates the spatiotemporal evolution of these spiral waves. (e) Time series data for are recorded at the point , shown by an asterisk, for . (f) Plot of the inter-beat interval (ibi) versus the beat number , and (g) the power spectrum (of ) versus the frequency for the control case (black circles), zero-sided coupling (gray squares), single-sided coupling (blue diamonds), and double-sided coupling (red triangles); these plots of ibi and are obtained from a time series of , with 400000 data points separated by 0.02 ms.