T wave often shows a kind of cardiac repolarization changes, T wave flattening sometimes has no special clinical significance, if T wave flattening continues to aggravate, it is often the manifestation of coronary heart disease myocardial ischemia and hypokalemia. 1. Mild T-wave flattening sometimes has no clinical significance. If it is only transient or mild T-wave flattening, it is called physiologic T-wave flattening. For example, T-wave flattening may occur in the case of emotional excitement, excessive tension or fatigue after staying up all night. 2. Coronary heart disease, myocardial ischemia. Some persistent T-wave flattening is a manifestation of coronary heart disease and myocardial ischemia. Sometimes it is often accompanied by chest tightness and panic, if you want to further clarify the diagnosis, coronary angiography can be performed. 3. Low blood potassium. Sometimes when the electrolytes in the body are disturbed and there is low blood potassium, low T-wave will also appear, which is mostly related to the low potassium content in the food intake, in this case, potassium should be replenished in time. In many cases, ECG only serves as a diagnostic reference, and the correct clinical diagnosis needs to be made by combining the patient’s symptoms, medical history and other cardiac examinations. If similar situation occurs, patients are advised to consult the doctor in time and follow the doctor’s instructions for treatment.