Partial-lead ST-T changes often indicate partial-lead myocardial ischemia. For coronary artery disease, the site of cardiac ischemia can be reflected on the ECG, including anterior, lateral, inferior, and posterior myocardial ischemia, which often has ST-T changes in the corresponding leads on the ECG. Therefore, for partial lead ST-T changes, they often indicate myocardial ischemia in specific parts of the heart and can suggest which coronary vessel is responsible for myocardial ischemia, which can be used to guide coronary interventional treatment. The diagnosis of coronary artery disease mainly relies on patient symptoms, signs, laboratory tests suggesting relevant evidence of myocardial ischemia, and coronary imaging to clarify the diagnosis if necessary. In addition, the detection of myocardial damage markers can be used for the staging of coronary artery disease, and ST-T changes in some leads of ECG can often indicate which branch of coronary artery is the myocardial ischemia caused by vascular lesions.