Usually, myocardial infarction has the highest mortality rate from 2-6 hours after the onset of the disease. Myocardial infarction is mainly due to ischemia or necrosis of the myocardium caused by insufficient blood supply to the coronary arteries, and the main clinical manifestation is severe pain in the chest. In general, mild myocardial infarction does not affect heart function, while severe myocardial infarction can easily lead to sudden death. Patients often have multiple recurrent manifestations of myocardial ischemia before myocardial infarction occurs. Angina pectoris may appear 7-14 days before myocardial infarction, mainly manifesting as chest pain and chest tightness symptoms after activity, and the symptoms can disappear rapidly after rest. If a patient has a myocardial infarction, 2-6 hours can lead to the patient’s death. It is necessary to promptly call the emergency number 120, try to maintain absolute rest, and at the same time contain aspirin, quick-acting heart pills or nitroglycerin tablets to improve the blood supply to the heart muscle. In addition, patients with myocardial infarction should pay attention to rest, control blood pressure, blood sugar, reasonable diet and appropriate exercise.