Figure 4a. Spiral wave breakup due to discordant alternans. Movie (1,254K) 

Figure 4b. Suppression of alternansinduced breakup by electrotonic effects (APD restitution slope = 4). Movie (588K) 

Figure 8a. Suppression of alternansinduced breakup by memory effects (APD restitution slope = 2). Movie (439K) 

Figure 5a. Spiral wave breakup in an anatomical model of rabbit ventricles due to discordant alternans. Movie (2,391K) 

Figure 5b. Suppression of alternansinduced breakup by electrotonic effects in an anatomical model of rabbit ventricles (APD restitution slope = 4).
Movie (839K) 
Applet 
1dimensional map. Iterative map showing how alternans can originate in a single cell with no memory when the slope of the APD restitution curve is greater than one. 
Applet 
1D ring with alternans. Simulation showing how discordant alternans develops in a ring as the ring size is decreased. 
Applet 
1D ring with some alternans suppression. Simulation using Model 2a showing how discordant alternans develops only for an intermediate range of ring sizes, with no alternans occuring for large and small sizes (correlates with Figure 3a). 
Applet 
1D ring with no alternans. Simulation using Model 2c showing how discordant alternans is completely supressed for all ring sizes even when the slope of the APD restitution curve is as high as four (correlates with Figure 3a). 