Transapical Beating-heart Septal Myectomy in Patient With Hypertrophic Obstructive Cardiomyopathy

Inclusion Criteria: 1. Patients whose resting or provoked left ventricular outflow tract gradient \> 50 mmHg, and maximal ventricular septal wall thickness ≥ 15 mm. 2. Patients with heart function of New York Heart Association ≥ class II. 3. Patients with drug-refractory symptoms or intolerable to pharmaceutical therapies. 4. Patients who was informed the nature of the clinical trial, consented to participate in all of the activities of the clinical trial, and signed the informed consent form. Exclusion Criteria: 1. Patients who were pregnant. 2. Patients who had concomitant diseases such as intrinsic valvular disease or coronary artery disease that needed open-heart surgery. 3. Patients who had severe heart failure with left ventricle ejection fraction \< 40%. 4. Patients whose estimated life expectancy \< 12 m. 5. Patient who were non-compliant. 6. Patients under circumstances which were considered not suitable or prohibitive for participating the clinical trial at the discretion of the attending medical team and the researchers.