According to its clinical symptoms, coronary artery disease can be divided into 5 types: 1. Angina pectoris type: It manifests as a feeling of pressure and stuffiness behind the sternum, accompanied by significant anxiety, lasting 3 to 5 minutes, often spreading to the left arm, shoulder, jaw, throat, back, and may also radiate to the right arm. Sometimes these areas can be involved without affecting the posterior sternal region. The onset of angina is called exertional angina when there is an increase in myocardial oxygen consumption due to exertion, emotional stress, cold, or a full meal, and is relieved by rest and nitroglycerin. Sometimes angina pectoris is atypical and may manifest as tightness of breath, syncope, weakness, belching, especially in the elderly. Stable and unstable angina are classified according to the frequency and severity of attacks. Stable angina refers to exertional angina that has been attacked for more than one month, and its attack site, frequency, severity, duration, the size of the exertion that induced the attack, and the amount of nitroglycerin that can relieve pain are basically stable. Unstable angina refers to an increase in the frequency, duration and severity of the original stable angina attack, or a new attack of exertional angina (occurring within one month), or an attack of angina at rest. Unstable angina is a precursor to acute myocardial infarction, so you should go to the hospital as soon as you find it. 2, myocardial infarction type: about a week before the infarction occurs there are often prodromal symptoms, such as angina pectoris that occurs at rest and during light physical activity, accompanied by significant discomfort and fatigue. The infarction is characterized by persistent severe pressure, stuffiness, or even knife-like pain, located behind the sternum, often spreading to the entire anterior chest, with the left side being the heaviest. Some patients can extend the left arm ulnar side downward, causing a tingling sensation in the left wrist, palm and fingers, and some patients can radiate to the upper limbs, shoulder, neck and jaw, mainly on the left side. The pain is consistent with the previous angina, but lasts longer and is more severe, and is not relieved by rest or nitroglycerin. Sometimes it presents as epigastric pain, which can be easily confused with abdominal disease. It is accompanied by low-grade fever, irritability, excessive and cold sweats, nausea, vomiting, palpitations, dizziness, extreme weakness, dyspnea, and a sense of near death, lasting more than 30 minutes and often several hours. This condition should be seen immediately. 3. Asymptomatic myocardial ischemia type: Many patients have extensive coronary artery obstruction but have not felt angina, and some patients even did not feel angina at the time of myocardial infarction. Some patients are detected only after sudden cardiac death has occurred and myocardial infarction is detected during routine physical examination. Some patients have arrhythmias due to ischemic manifestations on the ECG, or are only detected by coronary angiography because of a positive exercise test. These patients have the same chance of sudden cardiac death and myocardial infarction as those with angina pectoris, so they should pay attention to their usual cardiac care. 4, heart failure and arrhythmia type: some patients had angina attacks, later due to extensive lesions, extensive myocardial fibrosis, angina pain gradually reduced to disappear, but the performance of heart failure, such as tightness, edema, weakness, etc., and a variety of arrhythmias, manifested as palpitations. There are also some patients who never have angina, but directly manifest heart failure and arrhythmia. 5.Sudden death type: It refers to the unpredictable and sudden death caused by coronary heart disease, resulting from cardiac arrest within 6 hours after the appearance of acute symptoms. It is mainly caused by the abnormal electrophysiological activity of cardiomyocytes due to ischemia, and the occurrence of severe arrhythmias.