Treatment Response to Mavacamten in Patients With Obstructive Hypertrophic Cardiomyopathy: 96-Week Results From the EXPLORER Cohort of the MAVA-Long-Term Extension Cardiac Magnetic Resonance Imaging Substudy

All participants provided written informed consent?a In EXPLORER-HCM. patients received mavacamten or placebo for 30 weeks. After trial completion and a variable washout period, patients could enroll in MAVA- LTE. with initiation of mavacamten 5 mg/day and echocardiography-guided titration. CMR assessments were conducted as previously detailed? with analyses at baseline and week 30 of EXPLORER-HCM and weeks |24 and 96 of MAVA-LTE (data extraction on March 9, (2023). Exploratory end points included left ventricular (LV) mass index, LV maximum wall thickness, volumes land function (left atrial volume maximum index, LV end- diastolic volume index, LV end-sys tolic volume index, and myocardial contractile fraction), focal and diffuse mocar- dial fibrosis (6-SD late gadolinium enhancement [LGE] and average extracellular volume fraction), and LV ejec- tion fraction (LVEF).