While miR-21, -133, -150, -195, and -214 regulate cardiomyocyte hypertrophy, miR-1/-133 and miR-208 have been elucidated to influence myocardial contractile function. In addition, miR-21, -24, -133, -210, -494, and -499 appear to protect myocytes against I/R-induced apoptosis, whereas miR-1, -29, -199a, and -320 promote apoptosis. Myocardial fibrosis can be regulated by the miR-29 family and miR-21.