Patients with coronary artery disease do not always end up with symptoms of heart failure. Coronary artery disease is mainly caused by insufficient blood supply to the heart due to coronary artery stenosis, and the main manifestations are divided into several types: First, there is asymptomatic myocardial ischemia, which usually has no symptoms. Secondly, the most typical is coronary artery disease, angina pectoris type, which often presents with episodes of retrosternal pain lasting from a few minutes to ten minutes, sometimes relieved after rest or medication. Finally, the most serious is myocardial infarction, which is mainly caused by complete occlusion or spasm of the coronary artery, resulting in myocardial necrosis, and in the most serious cases, the enlarged heart, heart failure, respiratory distress and arrhythmia, and finally sudden death.