Effect of Mavacamten Therapy on Myocardial Systolic Function Assessed by 3D Echocardiography

Myosin inhibitors represent a novel therapeutic strategy for obstructive hypertrophic cardiomyopathy (oHCM), directly targeting sarcomeric hypercontractility to reduce left ventricular outflow tract obstruction.

Three patients with symptomatic oHCM enrolled in Italy's Early Access Program for mavacamten underwent 2D and 3D echocardiographic assessment at baseline and at 6 months. All experienced symptomatic improvement and left ventricular outflow tract obstruction reduction, accompanied by a modest decline in global left ventricular ejection fraction (LVEF) at 6 months follow-up. A 3-dimensional analysis revealed that LVEF reduction primarily involved mid and apical segments, while the basal function remained stable.

These findings suggest that mavacamten selectively attenuates hypercontractility in relatively preserved myocardial regions rather than inducing global systolic dysfunction. Three-dimensional echocardiography provided novel insights into regional contractile adaptation, offering potential guidance for individualized dosing and monitoring.

Mavacamten-induced LVEF decline reflects regional hypokinesia, not global dysfunction. Three-dimensional imaging enhances understanding of treatment response in oHCM.