The main symptoms of coronary heart disease are chest pain and chest tightness. Depending on the type of coronary heart disease, the duration and relief of chest pain, attack triggers, and accompanying symptoms vary. The main symptoms of coronary heart disease are chest tightness and chest pain. The typical site of chest pain is behind the sternum, and it may radiate to the left chest, the back of the left shoulder, the front inner side of the left upper arm; it may also radiate to the neck, pharynx, jaw and head; the nature of the pain is typically pressure-like, mostly accompanied by obvious chest tightness, and some patients have a sense of near death, which often forces patients to stop activities immediately. The onset of symptoms is mostly triggered by such factors as going upstairs, fast walking, exertion, full meal, cold, emotional excitement, etc. The symptoms can be relieved by quiet rest. Some patients have atypical symptoms, such as epigastric pain, subxiphoid discomfort, etc. Angina pectoris usually lasts less than 20 minutes. The symptoms can be relieved within 1-3 minutes after resting or taking nitroglycerin. The nature and location of chest pain in heart attack is similar to angina pectoris, but it is more intense and persistent, lasting for more than 20 minutes, and cannot be relieved by rest or nitroglycerin. The danger of coronary heart disease is mainly from two aspects, one is the necrosis of myocardial cells due to myocardial ischemia. Patients with myocardial infarction can have their lives reduced by stenting, bypass, and pharmacological thrombolysis, but complications such as heart failure, arrhythmias, and thrombosis and embolism can occur in the distant future. Patients may be hospitalized repeatedly for a long time, which brings a great burden to families. Another hazard is that it may lead to sudden death, and the most common cause of sudden death is malignant arrhythmia caused by coronary heart disease.