The st-t change can not be directly to determine whether the patient is mild or severe. st-t change can have no clinical significance, or it can represent myocardial ischemia. 1. No clinical significance: Some patients do not have any clinical symptoms, but the ECG with st-t changes may be due to early repolarization, late night, emotional excitement, etc. It is recommended to review and observe regularly. 2. Clinical significance: If patients with chest pain symptoms, check the electrocardiogram, there are st-t changes, sublingual nitroglycerin after chest pain relief, and st-t also returned to normal, this is a myocardial ischemia manifestation, considered angina pectoris occurs. In addition, pericarditis, myocarditis, anemia, hypertensive heart disease can lead to st-t changes. It is recommended to have st-t changes in ECG, go to the hospital in time to combine past medical history, blood routine, cardiac enzymes and protein markers of myocardial injury, dynamic electrocardiography, echocardiography, coronary CT and other tests, to clarify the cause of the disease, and then carry out the next step of the treatment program under the guidance of the physician.