The results showed that with the continuous maturation of cardiomyocytes, the MYH7/MYH6 ratio of KO hiPSC-CMs was gradually increased compared with WT hiPSC-CMs, and KO hiPSC-CMs showed a pathological phenotype of myocardial hypertrophy (Fig. 3H). This evidence concerns the gene MYH6 and cardiac hypertrophy.