Higher sensitivity to ouabain‐induced toxicity in human induced pluripotent stem cell‐derived cardiomyocytes than human adult heart tissue despite similar Na ⁺ /K ⁺ ‐ATPase pump current amplitudes

HiPSC-EHTs express NKA with biophysical characteristics and ouabain-sensitivity that are not different from human tissue. Action potential duration responses in EHT reproduces chamber-specific response pattern as seen in human heart. The higher sensitivity of EHTs to depolarize under ouabain-induced block of NKA needs to be considered when employing hiPSC-CM in drug research.