Effectiveness and Treatment Patterns of Mavacamten in Patients With Obstructive Hypertrophic Cardiomyopathy in Japan (MANAGE-HCM)

Inclusion Criteria: • Signed informed consent form (ICF): Participants, or their legally acceptable representative, must have signed and dated an Institutional Review Board (IRB)/Independent Ethics Committee (IEC)-approved ICF in accordance with regulatory, local, and institutional guidelines. This must be obtained before the performance of any protocol-related procedures. * Diagnosed with obstructive hypertrophic cardiomyopathy (HOCM) consistent with Japanese Circulation Society guidelines (2025), i.e., satisfy all criteria below: * Has unexplained left ventricular (LV) hypertrophy with nondilated ventricular chambers in the absence of other cardiac (e.g., hypertension, aortic stenosis) or systemic disease and with maximal LV wall thickness ≥ 15 mm (or ≥ 13 mm with positive family history of HCM). * Has Left Ventricular Outflow Tract (LVOT) peak gradient ≥ 30 mmHg (resting, Valsalva maneuver, or post-exercise). * Has documented Left Ventricular Ejection Fraction (LVEF) ≥ 55% at baseline. * Participants who meet any of the following criteria: * Participants who have previously received mavacamten continuously for ≥ 16 weeks * Participants who are currently receiving mavacamten * Participants who are scheduled to receive mavacamten * Treated with a stable dose of cibenzoline for at least 3 months prior to initiating mavacamten treatment. Tapered cibenzoline within 3 months prior to initiating mavacamten treatment is allowed if stable dose of cibenzoline was used for at least 3 months prior to tapering. * At least 18 years of age at the time of signing the informed consent. Exclusion Criteria: * Hypersensitivity to the active substance or to any of the excipients. * During pregnancy and in women of childbearing potential. * Treated with strong CYP3A4 inhibitors (itraconazole, clarithromycin, voriconazole, posaconazole, ritonavir, cobicistat, ceritinib, ensitrelvir fumaric acid, lonafarnib, josamycin, or mifepristone/misoprostol). * Severe hepatic impairment (Child-Pugh C). * Severe atrioventricular block or severe sinoatrial block. * Congestive heart failure. * Requiring dialysis. * Angle-closure glaucoma. * Tendency to urinary retention. * Treated with vardenafil hydrochloride hydrate, moxifloxacin hydrochloride, lascufloxacin hydrochloride (injection), toremifene citrate, fingolimod hydrochloride, siponimod fumarate, or eliglustat tartrate. * Mavacamten treatment within 8 weeks prior to baseline. Mavacamten treatment initiation was judged based on post-exercise LVOT peak gradient.