ST segment changes are a common presentation on the ECG, but they are not always pathologically significant and need to be of a certain magnitude to be pathologically significant. They are usually characterized by ST segment depression and elevation. 1. Depression: ST segment depression usually needs to be greater than 0.1mV to be considered as having pathological significance, suggesting that the patient’s myocardial ischemia, which is commonly seen in coronary heart disease, cardiomyopathy, etc. ST segment depression may also be caused by emotional excitement, poor rest, etc., which is usually of no pathological significance. 2. Elevation: ST segment elevation usually has pathological significance and should not be ignored. It is common in acute myocardial infarction, variant angina pectoris, acute pericarditis, acute viral myocarditis and so on. ST segment changes, we recommend that patients go to regular hospitals, improve the relevant examination, and follow the doctor’s instructions to deal with.