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 nonobstructive hypertrophic cardiomyopathy. This is a prospective, single-arm, single-center study.

Medical therapy is first recommended for patients with nonobstructive hypertrophic cardiomyopathy administrated at onset of heart failure symptoms. As the disease progresses, patients with global ejection fraction < 50% should be evaluated with respect to eligibility and motivation for heart transplant. However, for those with preserved ejection fraction and drug-refractory heart failure symptoms, there is still no optimal therapy. Some patients with increased left atrial volume and/or diastolic dysfunction can be recognized as a result of excessive myocardial hypertrophy, and the septal resection for these patients may be beneficial. However, conventional septal myectomy is hindered by the demanding expertise that is needed to sufficient resection of hypertrophied septal myocardium while guarantee safety. To increase the visualization and minimize the surgical injury of conventional septal myectomy, we 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 ventricular morphology and hemodynamics are evaluated each time after resection. Multiple resections are performed to tailor sufficient enlargement of left ventricular end-diastolic volume and improvement of mitral regurgitation, while preventing iatrogenic injuries. After transapical beating-heart septal myectomy, patients are scheduled to be seen for follow-up visits at discharge (about 7 days post operation) and 3 months.

Inclusion Criteria:

1. Patients whose 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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