A, Distances of RyR clusters to closest sarcolemma. B, Nearest neighbor distances of RyR cluster centers. C, Density of RyR clusters. The t-system and RyR arrangement were characterized in D, WGA and E, RyR image stacks, respectively, by the normalized magnitudes of longitudinal frequency. † p<0.05 versus control, * p<0.05 versus A6, # p<0.05 versus DHF.