Aficamten, a selective cardiac myosin inhibitor, demonstrated robust safety across 697 patient-years in 463 patients with obstructive hypertrophic cardiomyopathy. Only 0.9% of patients permanently discontinued treatment, with an exposure-adjusted incidence rate of 0.6 per 100 patient-years. Left ventricular ejection fraction below 50% occurred in 4.1% of patients, but no cases were associated with clinical heart failure attributable to the drug, and no patient experienced dangerous drops below 40%. This safety profile positions aficamten as a potentially transformative treatment for a condition affecting roughly 1 in 500 people globally. Hypertrophic cardiomyopathy causes dangerous heart muscle thickening that can lead to sudden cardiac death, particularly in young athletes. Current treatments are limited and often inadequate. Aficamten represents the next generation of myosin inhibitors, following mavacamten's approval, suggesting this drug class may revolutionize care for inherited heart muscle diseases. However, this integrated analysis is a preprint awaiting peer review, and the relatively short exposure duration means long-term effects remain unknown. The favorable safety data supports continued clinical development, but independent validation is essential.