Figure 3.

Panel (a) illustrates the repolarization map of the S1 beat that preceded the onset of spiral wave reentry shown in Figure 2. Isochrones of F_CaiD₈₅ were mapped at 40 ms duration. The line of functional propagation block around which the spiral wave reentry circulated developed at zones of crowded isochrones reflecting spatial dispersion of F_CaiD₈₅. Panel (b) shows two representative F_Cai signals recorded from two pixels in isochrones 160 and 360 ms and illustrate a 200 ms difference in F_CaiD₈₅