Myocardial infarction is a serious disease, usually a high-risk disease. If not treated in time, there will be many consequences. 1. It can lead to sudden cardiac death, and myocardial infarction can directly cause cardiac death. 2. Functional rupture of papillary muscles and dysfunction of papillary muscles will occur after myocardial infarction, which will lead to severe mitral or tricuspid valve insufficiency and secondary heart failure. 3. Heart rupture will occur after myocardial infarction. Heart rupture is the most terrifying complication of myocardial infarction and usually directly leads to a life-threatening situation for the patient. 4. It will cause ventricular septal defect. Ventricular septal defect is caused by the perforation of the necrotic myocardium after the patient has myocardial infarction, thus inducing heart failure. 5. Post-myocardial infarction syndrome. Post-myocardial infarction syndrome usually occurs in the 4th to 6th week after myocardial infarction, and there will be obvious arrhythmia and other conditions.