We often encounter patients who are diagnosed with myocardial ischemia, or coronary artery disease, because of persistent ST-T changes on the ECG, which is a misconception. Persistent ST-T changes on the general ECG are not the basis for chronic myocardial ischemia, nor can coronary artery disease be diagnosed on this basis. The diagnosis of coronary artery disease by general ECG is usually more significant in two cases: 1. Patients with angina pectoris symptom attack is accompanied by ST-T changes on ECG, and after the symptoms disappear, the ST-T changes on ECG also slowly recover (not necessarily fully synchronized). 2, acute myocardial infarction, which is more complex and requires professional judgment and simultaneous examination of cardiac enzymes.