T wave mainly reflects ventricular repolarization, sinus rhythm T wave changes, may suggest the emergence of myocardial ischemia, anemia, hypokalemia and other discomforts. 1. Myocardial ischemia: due to coronary artery stenosis, blood perfusion to the heart is reduced, myocardial oxygen consumption is increased, oxygen supply is insufficient, and pain in the anterior region of the heart occurs, electrocardiogram shows ST-segment changes, anterior myocardial ischemia is manifested as T-wave flattening, inverted, and T-wave is elevated in the case of inferior myocardial ischemia, which should be sought for medical treatment in a timely manner. 2. Anemia: when patients have anemia, red blood cells decrease, oxygen function decreases, cardiomyocytes and brain cells are sensitive to hypoxia, electrocardiogram shows sinus rhythm T-wave changes, T-wave abnormal fluctuations and ups and downs, and if it has an impact on the life, they should consult a doctor in time. 3. Hypokalemia: Hypokalemia is caused by a decrease in the concentration of potassium ions in the blood serum, which is lower than the normal physiological concentration, and is often manifested as weakness of the limbs, nausea, vomiting, etc. The electrocardiogram shows changes in the T wave of sinus rhythm, and the T wave is wide and low or symmetrically inverted, which is generally more serious, and medical attention should be sought in a timely manner. Sinus rhythm T wave changes, may indicate that the body has abnormalities, should promptly seek medical treatment, under the guidance of the doctor.