T-wave changes are mainly categorized into low T-wave, high-acuity T-wave, and T-wave inversion. 1. Low T-wave: mainly when performing ECG examination, there is low T-wave, which means that the shape of T-wave is low and flat, and may be lower than the horizontal line. It can be seen in hypokalemia, myocardial ischemia and so on. 2. Hyperacute T-wave: mainly when performing ECG, there is a hyperacute T-wave, that is, the T-wave is towering, like a signal tower, with a large area at the bottom, and the higher you go, the smaller the area is, and finally it will form a tower-tip-like change. It is seen in hyperkalemia, early repolarization syndrome and so on. 3. T-wave inversion: T-wave inversion mainly appears on ECG, that is, the direction of T-wave is opposite to the direction of T-wave in normal ECG. It can be seen in angina pectoris, myocardial infarction, cardiomyopathy and so on. It is recommended to go to the cardiology department of the hospital in time to get a clear diagnosis and timely treatment for ECG abnormalities.