The primary purpose of this study is to evaluate the feasibility, the safety and the efficacy of the transapical beating-heart septal myectomy for the treatment of hypertrophic obstructive cardiomyopathy. This is a prospective, single-arm, multi-center study.

Surgical septal myectomy remains the gold standard for the treatment of hypertrophic obstructive cardiomyopathy. However, conventional septal myectomy is hindered by the demanding expertise that is needed to sufficient relieve the obstruction of the left ventricle outflow tract while guarantee safety. To increase the visualization and minimize the surgical injury of conventional septal myectomy, the investigators have invented a novel beating-heart myectomy device. Through a mini-thoractomy, septal myectomy could be accomplished via a transapical access in the beating heart using the beating-heart myectomy device. The whole process of resection is monitored, navigated, and evaluated by real-time transesophageal and transthoracic echocardiography. Left ventricle outflow tract gradient and the grade of mitral regurgitation are evaluated each time after resection. Multiple resections are performed to tailor sufficient relief of left ventricle outflow tract obstruction and mitral regurgitation, while preventing iatrogenic injuries. After transapical beating-heart septal myectomy, participants is scheduled to be seen for follow-up visits at discharge (about 7 days post operation) and 3 months.

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.

All of the conclusive participant data, after removing the individual information of privacy, will be uploaded as supporting information when publishing the current study

After the current study is published.

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