In case of myocardial ischemia, the initial determination is made by electrocardiogram. The ECG manifestations of myocardial ischemia include ST-segment depression or arch-back elevation, and T-wave inversion or hyperacusis. In addition, pathological Q waves may also be present, which are typical ECG signs of myocardial ischemia. In addition to ECG, cardiac ultrasound, coronary CT, and coronary angiography are needed to clarify the extent of myocardial ischemia and the presence of myocardial infarction. Based on these tests, the degree of luminal stenosis can be clarified to determine the next treatment plan, such as conservative drug treatment or coronary stenting surgery, or even surgical bypass surgery, which can improve the myocardial ischemia.