Effect of mavacamten on left ventricular diastolic function and left atrial remodelling in obstructive hypertrophic cardiomyopathy

• Mavacamten improves diastolic function in obstructive hypertrophic cardiomyopathy • Significant reduction in left atrial volume and E/E′ ratio was observed after 5 months • Clinical status and NT-proBNP improved alongside haemodynamic parameters • Atrial strain parameters (PALS, PACS) decreased despite reduced atrial volume • Early real-world data support the benefits of mavacamten beyond clinical trials Background: Obstructive hypertrophic cardiomyopathy (HCM) is characterized by dynamic left ventricular outflow tract (LVOT) obstruction, leading to disabling symptoms. Mavacamten, a selective cardiac myosin inhibitor, improves obstruction and symptoms. Its beneficial effects on left ventricular diastolic indices have been documented, whereas its impact on left atrial strain has only recently been explored. Aim: To assess the effect of mavacamten on diastolic function, left atrial remodelling and ventricular filling pressures in patients with obstructive HCM. Methods: In this prospective, single-centre study, 55 symptomatic patients with obstructive HCM (mean age 68 ± 12 years, 40% male) were evaluated before and after individualized mavacamten titration. Echocardiographic, clinical and biomarker parameters were collected at baseline and after stabilization: left atrial end-systolic volume (LAESV), E/E′ ratio, E/A ratio, peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS), LVOT gradients, left ventricular ejection fraction (LVEF), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and NYHA class. Results: After a mean titration of 5 months (final median maintenance dose 5 mg/day), NYHA class improved from 2.5 to 1.4 ( P