Low flat T-wave alteration in sinus rhythm is generally defined as a decrease in T-wave amplitude. The causes of low T-wave alteration in sinus rhythm may be myocardial ischemia and autonomic dysfunction. 1. Myocardial ischemia: T-wave flattening is generally considered to be related to myocardial ischemia, and the possibility of myocardial ischemia is relatively high when accompanied by obvious clinical symptoms, or even T-wave inversion. Common in myocardial infarction. If angina pectoris occurs at the same time, you can take nitroglycerin, compound danshen tablets and other drugs to relieve. Usually should pay attention to regular life, regular rest, avoid strenuous exercise, do not smoke and do not drink alcohol. 2. Autonomic dysfunction: In addition to heart disease, autonomic dysfunction can also cause T-wave flattening. In this case, it is necessary to combine with other clinical symptoms such as chest pain, dyspnea, chest tightness, etc. It is also necessary to combine with cardiac ultrasound, coronary arteriography and other related imaging tests to further clarify the cause of the disease. If there are uncomfortable symptoms should be timely diagnosis and treatment, so as to avoid delaying the condition. Sinus rhythm T-wave changes in low level need to pay attention to, go to the hospital in time for further examination, clear cause, targeted treatment.