Myocardial enzyme profile is mainly to check the degree of myocardial injury, which will be significantly elevated in myocardial infarction, as follows: 1. creatine kinase and creatine kinase isoenzyme: it starts to rise in 2-4h after infarction, peaks in 24-36h, and can return to normal in 3-5 days, in addition to diseases that can see elevated creatine kinase, including angina pectoris, pericarditis, polymyositis, cerebrovascular accident, etc.; 2, Lactate dehydrogenase: In addition to heart attack, it can also be elevated in viral hepatitis, liver cirrhosis, pulmonary infarction, leukemia and malignant tumor; 3. α-hydroxybutyrate dehydrogenase: In addition to heart attack, it can be elevated in other diseases such as viral myocarditis, anemia and some liver diseases; 4. aspartate aminotransferase: In addition to acute myocardial infarction, it can be elevated in toxic 4. aspartate aminotransferase: besides acute myocardial infarction, it can also be elevated in diseases such as toxic hepatitis, liver cancer, cirrhosis, pulmonary embolism and nephritis.