Endpoints and follow-up data
The clinical status of the participants was ascertained through telephone interviews at least once a year after septal myectomy. Those patients who died were treated as the endpoints, and the follow-up time was defined as their time of death. The last follow-up of the survivors was conducted in June 2018. The clinical endpoints in this study were defined as all-cause death, cardiovascular death, and nonfatal MI. The combined endpoints include the former three endpoints. Cardiovascular death was defined as any death with no clear non-cardiac cause. MI was diagnosed according to the standard definition (serum cardiac biomarker elevation with symptoms of ischemia and/or ECG changes indicative of new ischemia/infarction).