Real-World Assessment of Mavacamten's Impact on Left Ventricular Systolic and Diastolic Functions in Obstructive Hypertrophic Cardiomyopathy: A 1-Year Single-Center Observational Study

Abstract

Real-world data on the effects of mavacamten on diastology and global longitudinal strain (GLS) in symptomatic patients with obstructive hypertrophic cardiomyopathy (oHCM) are limited. We share our experience with mavacamten over a 24-week period at an HCM Center of Excellence. Sixty-one adults with symptomatic oHCM who started on mavacamten between March 2023 and February 2024 were retrospectively identified. All patients had an electrocardiogram performed at each clinic visit, and 72-hour Holter monitoring was performed at 12- and 24-week visits. The mean age was 57.2 ± 14.5 years; 32 (51.6%) patients were female. Of the 61 patients, 45 completed a 24-week period and were the main subject of this study. After 6 months of treatment, the proportion of patients in Grade 1 diastolic dysfunction increased from 26.6% to 62.2%, p = 0.001, and the proportion in Grade 2 diastolic dysfunction decreased from 66.6% to 35.5%, p = 0.006; 26.7% (n = 12/45) of patients improved by 2 New York Heart Association functional classes and 46.7% (n = 21/45) by 1. GLS remained stable over time. At week 24, 35 of 45 patients (77.7%) had a left ventricular outflow tract gradient ≤30 mmHg. No arrhythmia burden or major side effects were reported. Left ventricular ejection fraction remained above 55% in all but 1 patient, who recovered within a month. In conclusion, our experience of significantly improved diastology and stable GLS after mavacamten treatment aligns with trial outcomes. Longitudinal investigations are needed to further assess the long-term impacts.