Dilated cardiomyopathy (DCM) is cardiac disease characterized by increased left ventricular chamber volume and decreased systolic function. DCM patient-specific human induced-pluripotent stem cells-derived cardiomyocytes (DCM-hiPSC-CMs) were generated. We found that uniaxial stretch elicited a cytosolic [Ca 2 + ] i rise in hiPSC-CMs. Compared to control-hiPSC-CMs, DCM-hiPSC-CMs displayed a greater magnitude of [Ca 2 + ] i responses to the cell stretch of 10–15% elongation in length. This stretch-induced [Ca 2 + ] i rise was abolished by removal of extracellular Ca 2 + and markedly attenuated by TRPV4 inhibitors HC-067047 and RN-1734. Application of nifedipine and tranilast also reduced the [Ca 2 + ] i response but to a lesser degree. Moreover, the augmented [Ca 2 + ] i was decreased by cytochalasin D treatment. Taken together, our study for the first time demonstrated an abnormal TRPV4-related mechanosensitive Ca 2 + signaling in DCM-hiPSC-CMs. [ABSTRACT FROM AUTHOR]