A. Bifurcation diagrams of peak [Ca2+]i (top) and SR Ca2+ load (bottom) versus LCC cluster size (nLCC) for control gLCC (open circle) and 50% gLCC block (filled circle) with ϕ=0. B. Bifurcation diagrams of peak [Ca2+]i (top) and SR Ca2+ load (bottom) versus LCC cluster size with control gLCC and ϕ=50%. C. Percentage of concordant and discordant alternans for nLCC=3, 6, 10, and 14 with ϕ=0. D. Same as in C, but with ϕ=50%. Cell thickness was Lz=32 CRUs. PCL=300 ms. For each nLCC, 20 simulations were performed, each with a randomly generated uniform TT network structure.