Check whether there is myocardial ischemia, mainly including the following aspects: 1, check the electrocardiogram, especially when the symptoms of myocardial ischemia to do electrocardiogram, easy to find active myocardial ischemia. It is better to do dynamic electrocardiogram if it occurs more often at night to help detect the problem.2. Cardiac ultrasound, which mainly examines the structure and function of the heart, especially the ischemic myocardium is prone to hypokinesis, which can be shown on the ultrasound.3. Coronary angiography or coronary CTA, which are two tests to directly see if there is narrowing of the blood vessels in the heart, so as to see if there is myocardial ischemia. For patients with obvious symptoms of coronary artery disease but normal ECG and cardiac ultrasound, or patients with coronary artery disease who still have episodes of chest pain and tightness after standard medication, it is recommended to do this test to further guide the treatment.