Myocardial infarction, also known as myocardial infarction, is a serious type of coronary heart disease. Depending on the onset, it can be divided into acute myocardial infarction and old myocardial infarction. Acute myocardial infarction is a blockage of the coronary arteries supplying blood to the heart, resulting in acute severe ischemia of the myocardium, which occurs if it lasts for more than half an hour. In patients with acute myocardial infarction, if chest pain occurs within 12 hours (especially within 6 hours), the earliest opening of the blocked coronary artery is one of the main treatments, and among these treatments, interventional therapy is preferable to intravenous thrombolytic therapy. However, the need for intervention in patients who have been infarcted for some time (i.e., old myocardial infarction) depends mainly on the patient’s clinical condition and the results of coronary angiography to further determine the necessity of intervention and the feasibility of interventional procedures. ”Necessity” refers to the need for intervention, which depends on the presence or absence of viable myocardium. Theoretically, the ischemic myocardium will be completely necrotic or infarcted after 12 to 24 hours after the blockage of the vessel. For a patient with complete myocardial infarction, it is not meaningful to perform interventional treatment on the infarcted vessel, although there is no harm in opening the vessel. In practice, a small percentage of myocardium survives but remains in a state of severe ischemia or even near death, mainly due to recanalization of the blocked coronary artery (e.g., thrombus dissolution, release of coronary artery spasm), formation of collateral circulation, or recurrent episodes of severe ischemia that cause the myocardium to adapt to ischemia (also called ischemic pre-adaptation) when myocardial infarction occurs. Some of the following signs suggest the presence of viable myocardium: the patient still has chest pain and tightness after myocardial infarction; coronary angiography shows that the coronary artery at the infarct site is not completely blocked or that there is collateral circulation to the infarcted myocardium; there are also special radionuclide tests that can be used to determine the presence or absence of viable myocardium. As long as there is surviving myocardium, patients who still have symptoms of chest tightness, chest pain, cardiac insufficiency and unstable condition after infarction should still actively undergo coronary angiography and interventional treatment or coronary artery bypass surgery. It should also be noted that the reappearance of symptoms such as chest pain after myocardial infarction does not necessarily mean that ischemic myocardium still exists at the original infarct site, but also that other non-infarcted vessels may have problems. In this case, interventional treatment is not only to address the vessels at the infarct site, but more importantly, to address the vessels that have been severely stenosed but not yet infarcted. In cases where the infarct area is small, the post-infarct cardiac function is good, and the patient does not show any discomfort, drug therapy alone can be considered, but one should never assume that the disease is well and not take any treatment. According to foreign studies, in those with complete occlusion of a single coronary artery or those with multiple coronary artery lesions with complete occlusion, the rate of death after coronary artery opening was significantly reduced and cardiac function was improved. From this perspective, coronary angiography and intervention should be performed more aggressively for patients after myocardial infarction. ”Feasibility” refers to the ease of successful intervention, which depends largely on whether the coronary lesion is a completely blocked lesion and the length of the blockage, followed by whether there is severe calcification, bending, and other pathology in the coronary artery. Although we have significantly improved the success rate of opening chronic blocked vessels by using special guidewires and other materials, for vessels that have been completely blocked for a long time (longer than six months), there are still difficulties in interventional treatment, relatively low success rate, high cost, long operation time and high restenosis rate after opening. In contrast, for lesions in which the coronary artery is not completely blocked, intervention is a relatively simple procedure with a high success rate and low risk. In conclusion, the decision to perform interventional procedures in patients after myocardial infarction depends on a comparison of the benefits and risks that the procedure can provide. For cases with little benefit and high risk, interventional procedures should not be performed if the patient has no obvious clinical symptoms after myocardial infarction or if the presence or absence of surviving myocardium cannot be determined and the vessel has been blocked for a relatively long time. For cases with high benefit and low risk, such as patients who still have obvious symptoms after myocardial infarction, but the vessel has not been blocked for a long time or is not completely blocked, interventional procedures should be actively taken. For cases with high benefit and high risk, it is more difficult for physicians to make decisions. For example, if a patient has obvious symptoms after myocardial infarction and the vessel has been completely blocked for a long time, whether to take interventional surgery or coronary artery bypass surgery depends on the physician’s surgical experience and grasp of the patient’s condition.