An electrocardiogram (ECG) is usually able to detect angina when symptoms of angina attack occur, while an ECG may not be able to detect angina when it does not occur or when symptoms are in remission. Angina pectoris is a symptom of heart disease, and angina pectoris is usually associated with myocardial ischemia, and an electrocardiogram can reflect the presence of myocardial ischemia. Therefore, if you go to the hospital in time at the time of chest pain, improve the electrocardiogram is possible to find myocardial ischemia, but angina pectoris is usually a short period of time, lasting from a few minutes to ten minutes, so the symptoms are more relieved in the hospital, and the electrocardiogram may be no abnormal performance. The patient has pressure and suffocating pain behind the sternum, which is paroxysmal and related to exertion and emotional excitement, and can be relieved by resting or taking nitroglycerin under the tongue, so it is considered to be angina pectoris, and it is possible to find out by going to the hospital to have an electrocardiogram done in a timely manner.