Sinus rhythm T-wave changes can be seen in normal physiological state, but also in myocardial ischemia, myocardial infarction, cerebrovascular accident and other pathological states. 1. Physiological state: ECG T-wave represents the potential change of ventricle during rapid repolarization, normal shape of T-wave morphology is asymmetric between two limbs, the slope of the first half of the gentle, and the slope of the second half of the steeper, at the same time, the T-wave in the thoracic leads can sometimes be as high as 1.2-1.5mV is still normal. In the neonatal period, its limb leads and right chest leads often appear T wave low flat, inverted, is a normal phenomenon. 2. Pathological state: Generally speaking, sinus rhythm T-wave changes are related to myocardial ischemia in coronary artery disease, and other diseases such as cardiomyopathy, myocarditis, valvular disease, pericarditis, cerebral vascular accidents (especially intracranial hemorrhage), etc., all of which can show such ST-T changes; Electrolyte disorders, such as low or high potassium, can also lead to autonomic dysregulation and nonspecific ST-T changes after taking certain drugs, such as digitalis and quinidine. Therefore, if T-wave changes in sinus rhythm occur, further examination and treatment should be carried out in a timely manner as prescribed by the doctor.