Patients
We included 823 consecutive patients with HOCM evaluated at the Fuwai Hospital in Beijing between 2011 and 2017. All patients underwent coronary arteriography. MB was defined as an epicardial coronary artery systolic compression of ≥50% of the diameter on coronary arteriography (a representative myocardial bridge is shown in Figure 1). In this study, the MB group was defined as patients with HOCM complicated with MB and the non-MB group as HOCM patients without MB. The diagnostic criteria and surgical indications of HOCM were consistent with the 2011 American Heart Association/American College of Cardiology (AHA/ACC) guidelines, which mainly include unexplained septal hypertrophy with a thickness of >15 mm.7 The indications for septal myectomy were severe symptoms or syncope or near-syncope despite optimal medical therapy and an LV outflow tract (LVOT) gradient >50 mmHg at rest or with provocation. We excluded patients with coronary atherosclerosis heart disease and those younger than 18 years.
The study was approved by the Ethics Committee of Fuwai Hospital, Chinese Academy of Medical Sciences. Informed consent was obtained from all patients, in accordance with the principles of the Declaration of Helsinki.