Real-World Experience With Mavacamten in SRT-Eligible Obstructive HCM

BACKGROUND: Mavacamten, a cardiac myosin inhibitor, has been shown to improve symptoms and reduce left ventricular outflow tract gradients in obstructive hypertrophic cardiomyopathy (oHCM). However, real-world data regarding longer-term clinical outcomes, safety, and impact on septal reduction therapy (SRT) eligibility are limited. OBJECTIVES: The objective of the study was to evaluate the real-world effectiveness and safety of mavacamten in patients with oHCM who met guideline-based criteria for SRT. METHODS: We retrospectively reviewed patients with oHCM treated with mavacamten at our institution between April 2022 and December 2025 who met guideline-based SRT eligibility criteria. Clinical and echocardiographic outcomes were assessed at baseline and follow-up. Institutional SRT volumes before and after mavacamten approval were compared. RESULTS: Of the 84 patients treated with mavacamten, 53 met SRT eligibility criteria. The mean age was 67 ± 13 years, and 72% were females. Over a median follow-up of 82 weeks, resting left ventricular outflow tract gradients decreased from 51 ± 39 mm Hg to 4 ± 7 mm Hg and gradients with Valsalva from 79 ± 35 mm Hg to 9 ± 15 mm Hg (both P < 0.001). Overall, 49 patients (92%) improved by ≥1 NYHA functional class and no patients remained guideline-eligible for SRT or elected to undergo SRT at the time of most recent follow-up. Transient left ventricular ejection fraction reduction to <50% occurred in 6 patients (11%), and 7 (13%) developed new or recurrent atrial fibrillation. Institutional SRT volume declined significantly after mavacamten approval. CONCLUSIONS: In SRT-eligible oHCM, mavacamten use was associated with sustained hemodynamic and symptomatic improvement and was generally well tolerated in this real-world cohort. Institutional SRT volumes also declined during the post-mavacamten era.