Efficacy of Mavacamten in Reducing Cardiac Obstruction in an Elderly Patient with Hypertrophic Cardiomyopathy: A Case Study

BACKGROUND Mavacamten, a first-in-class cardiac myosin inhibitor, targets myosin adenosine triphosphatase to treat adults with moderate to severe symptomatic obstructive hypertrophic cardiomyopathy. Previous studies have demonstrated an approximate 50% reduction in left ventricular outflow tract pressure gradient in selected patients after 4 weeks of treatment. CASE REPORT We report the case of a 91-year-old man with hypertrophic cardiomyopathy, who presented with a longstanding history of progressive shortness of breath, unresponsive to treatment. After ruling out other potential causes such as coronary and pulmonary involvement, and performing serial ultrasound evaluations, we concluded that the worsening of his hypertrophic cardiomyopathy was the most likely underlying cause. After initiating Mavacamten therapy, the patient achieved a remarkable improvement, with over 80% reduction in left ventricular outflow tract obstruction observed within 4 weeks of treatment. He reports significant improvement in his shortness of breath both at rest and during daily activities. Dose titration and safety evaluation were performed through robust echocardiographic monitoring. CONCLUSIONS While our patient did not undergo genetic testing due to its high cost and limited clinical relevance, we believe that his remarkable response to this therapy may be linked to a genotype susceptibility enhancing the drug's pharmacodynamic effects, as suggested in the literature. This may have contributed to significant symptom relief and an improved quality of life. Further research is needed to better understand how genotype and phenotype influence treatment response, which could help refine our approach to optimizing non-invasive medical therapies.