In fact, acute coronary syndrome includes ST-segment elevation myocardial infarction, non-ST-segment elevation myocardial infarction, and unstable angina pectoris. There is also non-ST-segment elevation myocardial infarction, which is classified as non-ST-segment elevation myocardial infarction based on the changes in the electrocardiogram to observe whether the ST-segment is elevated or not, and those that are not elevated are classified as non-ST-segment elevation myocardial infarction. Why these three diseases are collectively referred to as acute coronary syndromes? In fact, their common pathogenesis is based on plaque instability, plaque rupture and secondary thrombosis in the coronary vessels of the heart. If the lumen is not completely blocked, the myocardial cells are not necrotic, and only the chest pain is symptomatic, it is judged as unstable angina. If the area of necrosis is quite large and the ST segment is obviously elevated, ST-segment elevation myocardial infarction is determined, and more often, the lumen is completely blocked. In non-ST-segment elevation myocardial infarction, most of the lumen is not completely blocked and the myocardium is partially necrotic. For example, in ST-segment elevation myocardial infarction, emergency surgery is preferred to open the vessels, while in non-ST-segment elevation myocardial infarction, different types of myocardial infarction require emergency surgery and some require elective surgery, but the drug treatment basically requires anticoagulation, lipid regulation and plaque stabilization, and basically the treatment principles are similar.