A) Representative APs recorded using perforated patch-clamp in day-40 hiPSC-CMs post-differentiation for the IWR1+SB differentiation compared to the IWR1 control. B) Cell capacitance reflecting cell size of hiPSC-CMs differentiated from the IWR1+SB condition (n=17) compared to the IWR1 control (n=15). C) AP parameters—maximum diastolic potential (MDP; IWR1: n=13, IWR1+SB: n = 15), AP amplitude (APA), maximum rate of rise (dV/dtmax), AP duration at 50% repolarization (APD50), and APl duration at 90% repolarization (APD90)—quantified from patch-clamp recordings of hiPSC-CMs from the IWR1+SB-differentiated cultures relative to the control. Data are shown as mean ± SEM (n = 10, except for where indicated). * denotes p < 0.05.