Chest pain caused by angina pectoris is mostly located behind the sternum, is compressed or stuffy pain, and radiates to the left upper limb or neck, mostly induced by physical activity, emotional excitement or eating, lasting 1-5 minutes each time, rarely more than 15 minutes. The duration of chest pain from acute myocardial infarction is longer, about half an hour to several hours, and the onset can be independent of activity. Others such as acute pericarditis, pulmonary embolism may also cause chest pain, combined with the pathogenesis, signs and other examination can be distinguished.