This study is a prospective interventional cohort study aimed at evaluating the therapeutic efficacy and clinical utility of Mavacamten-a targeted myosin inhibitor specifically developed for obstructive hypertrophic cardiomyopathy (HCM)-in patients with HCM characterized by mid-to-apical left ventricular obstruction.

Inclusion Criteria:

• Patients diagnosed with HCM according to the 2023 Chinese Guidelines for the Diagnosis and Treatment of Adult Hypertrophic Cardiomyopathy, meeting one of the following:

  1. Left ventricular wall thickness ≥15 mm at end-diastole in any segment as assessed by echocardiography or cardiac magnetic resonance imaging (CMR);

  2. Left ventricular wall thickness ≥13 mm in individuals with a confirmed pathogenic gene mutation or in genetically affected family members;

  3. Exclusion of other cardiovascular, systemic, or metabolic disorders that may cause ventricular hypertrophy.

     • Symptomatic non-outflow tract obstructive HCM patients (meeting criterion a and at least one of b or c):

  1. Presence of clinical symptoms such as dyspnea, chest pain, dizziness, palpitations, or syncope, with New York Heart Association (NYHA) functional class II-III;

  2. Maximal pressure gradient (PGmax) >30 mmHg in the mid-ventricle under resting or Valsalva maneuver as assessed by echocardiography;

  3. PGmax >30 mmHg in the apical region under resting or Valsalva maneuver on echocardiography.

     ③Ability to provide written informed consent (ICF) and any required privacy authorization prior to study enrollment.

     Exclusion Criteria:

     -

• Obstructive hypertrophic cardiomyopathy (HCM), defined as a maximal left ventricular outflow tract pressure gradient (LVOT-PGmax) ≥30 mmHg at rest and during the Valsalva maneuver on echocardiography;

  • Maximal right ventricular outflow tract pressure gradient (RVOT-PGmax) ≥16 mmHg at rest; ③ Left ventricular ejection fraction (LVEF) <50% on echocardiography;

    • Uncontrolled primary hypertension;

      • Moderate or severe aortic valve stenosis and/or primary mitral valve disease with severe mitral regurgitation; ⑥ Known infiltrative or storage disorders mimicking the HCM phenotype (e.g., Fabry disease, cardiac amyloidosis); ⑦ Presence of severe infections, hepatic dysfunction, renal impairment, or other serious conditions significantly affecting life expectancy.