Hypertrophic obstructive cardiomyopathy (HOCM) is an inherited myocardial disease which leads to the muscle in the wall of the heart growing and thickening to the point that it blocks blood flow exiting the heart with increasing risk of sudden cardiac death, heart failure, and atrial fibrillation. Surgical septal myectomy and alcohol septal ablation are two invasive therapies for drug-refractory symptomatic patients with HOCM. Unfortunately, some patients may be unsuitable for both the two procedures. Recently, stereotactic ablative radiotherapy, usually used for the treatment of tumours, was confirmed to be feasible, safe and effective in destroying abnormal tissue in heart by targeting high energy heavy ion beams at a specific area of the body precisely. In this study we will determine whether radiation ablation, can be used to destroy the thick heart muscle at the point of obstruction safely and effectively.

Inclusion Criteria:

• Male or female aged ≥ 18 years
• Drug-refractory symptomatic patients with HOCM
• Willing and able to give written informed consent

Exclusion Criteria:

• Enrolled in another clinical study.
• Patient unable to tolerate lying flat for one hour
• Pregnant Or Lactating Women
• With other contraindications for receive stereotactic ablative radiotherapy