Mavacamten in Obstructive Hypertrophic Cardiomyopathy and C282Y Homozygous Hereditary Hemochromatosis

BACKGROUND: Obstructive hypertrophic cardiomyopathy (HCM) and hereditary hemochromatosis (HH) rarely coexist. The therapeutic role of cardiac myosin inhibitors in this setting has not been described. CASE SUMMARY: A 67-year-old woman with known homozygous C282Y HH was referred for an abnormal stress echocardiogram. Cardiac magnetic resonance showed septal hypertrophy, systolic anterior motion of the mitral valve with left ventricular outflow tract obstruction, and iron overload. Owing to beta-blocker intolerance, mavacamten was started, with marked reduction in left ventricular outflow tract gradient. DISCUSSION: This case highlights the complexity of diagnosing and managing obstructive HCM in the context of HH. To our knowledge, this is the first reported use of mavacamten in this setting, demonstrating a favorable hemodynamic and clinical response. TAKE-HOME MESSAGES: Multimodality imaging is essential to differentiate primary obstructive HCM from HH-related cardiomyopathy. In this case, mavacamten was a well-tolerated alternative, though further data are needed to establish broader applicability.