Myocardial ischemia is a heart disease. Myocardial ischemia, also known as coronary artery disease, is caused by narrowing or spasm of the coronary arteries causing ischemia and lack of oxygen to the heart muscle. Coronary artery disease, also known as coronary atherosclerotic heart disease, is a type of heart disease, and once it occurs, patients will experience chest tightness, shortness of breath, and angina pectoris. After an electrocardiogram, cardiac ultrasound, coronary CTA and coronary angiography, the degree of coronary lumen narrowing is determined and the next treatment plan is decided. For example, treatment with coronary stenting, surgical open-heart bypass surgery, or even conservative treatment with medication can improve the symptoms of myocardial ischemia.