HF: heart failure; HFrEF: heart failure with reduced ejection fraction; RCT: randomized controlled trial; ACE: angiotensin-converting enzyme; ARB: angiotensin receptor blocker; VF: ventricular fibrillation; VT: ventricular tachycardia; LV: left ventricle; AMI: acute myocardial infarction; STEMI: ST-segment elevation myocardial infarction. The gene discussed is ACE; the disease is ventricular tachycardia.