When you have frequent boredom in the precordial region and the ECG results are normal, you may be reassured that you do not have coronary artery disease, but you should not take it lightly. A normal ECG does not rule out the presence of heart disease. It is important to know that ECG is not a very sensitive method for the diagnosis of coronary heart disease. The ECG detection rate of coronary heart disease is only 30%-50% during the non-onset period, while more than 50% of patients have normal ECG performance. In addition, the heart and coronary circulation have a greater compensatory capacity, and abnormalities are sometimes not easily detected at rest and during calmness, and often an exercise test with increased cardiac load is required to detect true changes in the ECG. However, when you see certain medical terms on the ECG report, you should not be worried and think you have heart disease, because an ECG alone cannot easily make a diagnosis of coronary heart disease, because there are many diseases such as cardiomyopathy, myocarditis, autonomic dysfunction, etc., which can produce the same ECG manifestations as coronary heart disease. Therefore, ECG is not a very specific method for the diagnosis of coronary artery disease. Although ECG examination is an important clinical reference for the diagnosis of coronary heart disease, it is not the only diagnostic criterion. Therefore, the clinical diagnosis of coronary heart disease must be made by a comprehensive and integrated judgment based on medical history, symptoms and certain special examinations before it can be done.