Real‐World Observations in Obstructive Hypertrophic Cardiomyopathy Patients Treated with Mavacamten: Evidence of Favorable Disease Modification

Background Mavacamten is commercially approved for use in symptomatic obstructive hypertrophic cardiomyopathy (oHCM) patients. This study evaluated its real‐world impact on symptoms, echocardiographic changes, and the need for septal reduction therapy (SRT) in oHCM patients treated at a multi‐hospital referral center. Methods We included 244 oHCM patients (mean age 64 years, 57% female, 21% with atrial fibrillation, 51% New York Heart Association [NYHA] Class III, 82% on beta‐blockers) treated with mavacamten for ≥3 months (171 for ≥12 months). Serial clinical and echocardiographic assessments were performed. Results NYHA Class distribution improved over time: at 3 months, 21% Class I, 61% Class II, 18% Class III; at 12 months, 36% Class I, 57% Class II, 8% Class III. After a mean of 1.02 years, significant improvements were observed in resting and post‐Valsalva left ventricular outflow tract (LVOT) gradients (‐31±33 and ‐57±46 mm Hg), interventricular septal thickness (‐1.7±4 mm), LV mass index (‐9.5±32 g/m 2 ), left atrial volume index (‐12±13 ml/m 2 ), E/e’ (‐5.5±6.4), LV‐global longitudinal strain (1.04±3.1%), and various left atrial and right ventricular strain measures (all p<0.05). Temporary interruption occurred in 8 patients (3.2%), and 3 (1.2%) discontinued mavacamten permanently. There were 2 noncardiac deaths, 7 heart failure admissions, 14 cases of new‐onset atrial fibrillation, and 1 patient required SRT. At the last visit, most patients were on 5 mg (49%) or 10 mg (26%). Conclusions In this real‐world cohort, mavacamten treatment was associated with sustained symptomatic and echocardiographic improvements, suggesting a favorable, disease‐modifying impact with minimal need for SRT.