MYK-461 is a small-molecule inhibitor interacting directly with cardiac myosin heavy chain to modulate myocardial contraction It specifically reduces myocardial contractility through inhibition of cardiac myosin ATPase enzymatic activity thereby limiting myosin-mediated phosphate release without affecting ADP dissociation rates In rodent cardiomyocytes MYK-461 demonstrates dose-dependent reductions in fractional shortening and sarcomeric force generation without impacting calcium transient dynamics Its inhibitory potency against cardiac myosin ATPase surpasses that observed for skeletal muscle isoforms In preclinical hypertrophic cardiomyopathy mouse models MYK-461 administration attenuates cardiac contractile function facilitating investigations into myocardial contractility regulation and potential therapeutic strategies against hypertrophic cardiomyopathy