Typical clinical manifestations of acute myocardial infarction: 1. The first symptom that appears is pain. Its location and nature are similar to angina, that is, sudden onset of severe pain in the posterior sternum or precordial region, radiating to the left shoulder and arm or elsewhere, but the pain is significantly worse and lasts longer, containing nitroglycerin to relieve. The patient often sweats profusely, is irritable, fearful or has a sense of near death. 2.The pain is often accompanied by frequent nausea, vomiting, intestinal flatulence and epigastric distension when the pain is severe, and eruption may occur in severe cases. 3. Fever, tachycardia, arrhythmia, etc. may occur one or two days after the onset of pain, and may be accompanied by fatigue, dizziness, fainting, etc. 4. Blood pressure often drops during pain, and shock may occur in severe cases. 5.Some patients may develop acute left heart failure, dyspnea, cough, cyanosis, irritability, pulmonary edema and coughing pink foamy sputum in severe cases. Atypical clinical manifestations of acute myocardial infarction: 1, no pain symptoms or pain is not intense, not to attract attention, generally seen in the elderly and people with diabetes. 2. The pain site is atypical. If some patients have pain in the upper abdomen, they are easily mistaken for gastric perforation or acute pancreatitis. 3. Some patients show shock or acute heart failure at the onset without obvious pain symptoms.