Heart attack usually refers to acute myocardial infarction, with the risk period being mainly within the first week after onset. The mortality rate is high, especially if it is accompanied by severe arrhythmia, shock or heart failure within a few hours. Acute myocardial infarction usually begins with necrosis of the ischemic myocardium within 20-30 minutes, and arrhythmias are most often seen within 24 hours; ventricular fibrillation is a common cause of death in the early stages of myocardial infarction. Due to the weakening of cardiac diastolic force after infarction, heart failure can also occur a few days before the onset of the disease, which can cause pulmonary edema and lead to death. Cardiac rupture can also occur within a week, causing heart failure and shock, which can lead to death. Serious complications of myocardial infarction mainly occur within the first week of the onset of the disease, but other complications in the later stages should not be ignored, such as embolism, which mostly occurs in the first 1-2 weeks of the disease, can be caused by thrombus dislodgement caused by arterial embolism, and severe pulmonary artery embolism can lead to sudden death. For acute myocardial infarction, it is emphasized that early detection, early hospitalization, as far as possible to save the myocardium, to prevent the infarction from expanding, so as to enable the patient to get through the acute stage and prevent sudden death.