ECG T-wave abnormality, which refers to the abnormal manifestations of ECG T-wave such as low flat or elevated, inverted, etc., can be seen in ventricular pre-systole, angina pectoris as well as physiologic changes. 1. Ventricular pre-systole: It can be manifested as the direction of ST segment and T wave is opposite to the direction of QRS main wave. It can be seen in normal people and patients with various heart diseases. The chance of ventricular pre-systole in normal people increases with age. Cardiac diseases are most common in patients with hypertension, coronary artery disease, cardiomyopathy, rheumatic heart disease and mitral valve prolapse. 2. Angina pectoris: (1) Stable angina: for patients with angina pectoris, there can be temporary myocardial ischemia caused by ST segment shift, and its T wave will also appear to change, but ST segment depression better reflects the specificity of myocardial ischemia. (2) Unstable angina: at this time, the T wave may appear to be low or inverted, and ST segment elevation or depression may also occur. When the dynamic change of ST segment is ≥0.1mV elevation or depression, it means that acute myocardial infarction or sudden death may occur. 3. T-wave abnormalities can also be seen in physiologic changes, for example, obese young people can also show T-wave inversion. If T-wave abnormality is found in ECG, it is recommended to follow the doctor’s advice for further examination and treatment, and not to take any action on your own, so as to avoid delaying the condition.