Long-term clinical benefit of mavacamten for hypertrophic cardiomyopathy in a patient with

Background: Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and is frequently complicated by left ventricular outflow tract (LVOT) obstruction. While most cases are caused by sarcomeric mutations, up to 10% represent non-sarcomeric or syndromic phenocopies, including Noonan syndrome (NS). Noonan syndrome is a RASopathy in which mutations in genes such as Case summary: We report a 29-year-old woman with long-standing obstructive HCM and NYHA class III symptoms, angina, and dizziness. Multimodality imaging demonstrated asymmetric septal hypertrophy (maximal wall thickness 20 mm), focal intramural late gadolinium enhancement, and dynamic LVOT obstruction reaching 55 mmHg during exercise. Owing to progressive obstruction, the patient was enrolled in the EXPLORER-HCM trial. During follow-up exceeding 5 years, treatment resulted in sustained reduction of LVOT gradients, improvement in functional status to NYHA class II, and complete resolution of angina and presyncope, without adverse effects. Genetic testing performed during trial participation identified a heterozygous likely pathogenic Discussion: This case report demonstrates durable clinical and haemodynamic benefit of myosin inhibition in