KCNN4 and arrhythmogenic right ventricular cardiomyopathy: In summary, this study revealed that in hiPSC-CMs from an ARVC patient, (i) NDPK-B and SK4 channels were upregulated, (ii) SK4 channels were activated, (iii) pacemaker activity was enhanced and (iv) the occurrence of arrhythmias was increased.