Fig. 5.

Plots of alternans at different BCLs and DIs. The mean (± SEM) alternans characteristics of AP amplitude (a, d), APD₉₀ (b, e) and θ’ (c, f) for WT (filled symbols) and RyR2 ^S/S (open symbols) hearts have been plotted as percentage variation between each beat as a function of BCL (a–c) and DI (d, e) AP magnitude displays an increasing degree of alternans with decreasing BCL and DI; however, this does not vary between genotypes. Similarly, a small degree of alternans is observed in the APD₉₀ and less so the θ’ with decreasing BCL and DI, but these do not vary significantly between the WT and RyR2 ^S/S hearts