Fig. 5

Spontaneous firing and beating rates in human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). A Action potential configurations in HCN4-overexpressing (left) and non-overexpressing (right) iPSC-CMs. B Comparison of spontaneous beating rates in HCN4-overexpressing and non-overexpressing iPSC-CMs (n = 6 in each) (The data are shown as means ± standard deviation.). C Responses to 10 µmol/L ivabradine and 1 µmol/L isoproterenol in HCN4-overexpressing iPSC-CMs (n = 8 in each) (The data are shown as means ± standard deviation)