Myocardial ischemia can be examined by coronary CTA, coronary angiography, electrocardiogram, cardiac ultrasound and blood tests. 1. Coronary CTA, coronary angiography: Coronary CTA examination can clearly see the lesions of coronary blood vessels, and if the vascular lesions cannot be clearly defined, further coronary angiography can be performed, and interventional therapy can be performed if necessary. However, coronary CTA and coronary angiography are invasive procedures and require hospitalization, so they are generally not the first choice for patients with mild disease. 2. Electrocardiogram (ECG): ECG can detect most of the myocardial ischemia, especially the comparison between ECG at the onset of the disease and the normal ECG, and it can also be examined by exercise plate test or ambulatory ECG, which is generally more accurate than the ordinary ECG in reflecting the presence of myocardial ischemia. 3. Cardiac ultrasound: Cardiac ultrasound can detect severe myocardial ischemia leading to weakening of ventricular wall movement or tendon rupture, etc., so that patients can be detected and treated early. 4. Blood test: patients can confirm the diagnosis of myocardial ischemia by drawing blood for cardiac enzymes, troponin, etc. However, blood tests are mainly used to confirm the diagnosis of acute myocardial infarction. When myocardial infarction is suspected, patients are advised to go to the hospital in time to avoid delay.