Severe myocardial ischemia may lead to conditions such as myocardial infarction, angina pectoris and even sudden death. Therefore, myocardial ischemia is more serious and needs to be taken seriously. Myocardial ischemia is a pathological state in which the blood infused into the heart is reduced, resulting in abnormal myocardial energy metabolism and decreased oxygen supply to the heart. There are two types of myocardial ischemia: mild and severe. Myocardial ischemia below 10% is mild myocardial ischemia, and patients may not have any symptoms; patients with myocardial ischemia over 10% or even 20% will have significantly reduced physical endurance and may even suffer sudden cardiac death. Therefore, for patients with weakness and chest tightness, it is recommended to do nuclear perfusion myocardial imaging evaluation to determine the severity of myocardial ischemia. Patients with severe myocardial ischemia should undergo blood source reconstruction to improve the blood supply function of the heart. It is possible to cure myocardial ischemia at an early stage. Patients are recommended to go to the hospital for timely examination and symptomatic treatment according to their conditions to avoid the development of mild myocardial ischemia into severe cardiomyopathy.