Heart attack is myocardial infarction, acute myocardial infarction is one of the most serious emergencies in internal medicine, if not treated in time, it may be life-threatening, so it is very important to recognize the symptoms of heart attack. The nature of chest pain in heart attack is similar to angina pectoris, but it is more intense and long-lasting: the duration of chest pain is more than 20 minutes, or even hours to days; it cannot be relieved by resting or taking nitroglycerin. The nature of the pain is tightening and squeezing, stuffy and suffocating, and occasionally there is a near-death-like fear, forcing patients to stop activities immediately. 2.The location of chest pain in heart attack is similar to angina: the typical location is in the middle and upper part of the sternum, and the range of pain is not limited, about the size of the fist and palm of the hand. It can also occur outside the chest, and the pain or discomfort in the upper abdomen (subxiphoid process) is common; followed by the left side of the left chest, the left back, the left shoulder, the left upper arm in front of the inner side up to the ring finger and the little finger; it can also be radiated upward to the neck, the pharynx, the lower jaw, the teeth and the head; it can be radiated downward to the abdomen, and a few of them can be radiated to the legs and the anus. To the right, it radiates to the right shoulder, arm, and even the inner side of the fingers of the right hand. 3, seizure triggers: often due to exertion, fatigue, satiety, cold, emotional excitement and other triggers; but quiet lying state can also occur. Accompanying symptoms: often accompanied by nausea, vomiting, pallor, cold sweat, dyspnea, panic, low blood pressure and so on. Typical chest pain is easier to recognize, angina patients should pay attention to identify atypical chest pain. When there is a combination of pain in a fixed location during exertion, we should also be highly vigilant.