Coronary heart disease, or coronary heart disease, is caused by myocardial ischemia due to narrowing of the coronary arteries, also known as ischemic heart disease. Coronary heart disease is mostly caused by coronary atherosclerosis, however, it can be called coronary heart disease only when coronary atherosclerosis causes functional and/or organic lesions of myocardial ischemia and hypoxia. The main clinical manifestations of coronary heart disease 1. angina pectoris. Angina pectoris is a common clinical syndrome caused by acute, temporary ischemia and hypoxia of the myocardium. The main symptom is paroxysmal pain or pressure in the precordial region, which may radiate to the precordial region or the left upper limb for several minutes, and the symptoms may be relieved with nitrate preparations or after a little rest. According to the cause and the degree of pain, it is customary to divide it into three kinds of angina pectoris: stable angina, unstable angina and variant angina. 2, myocardial infarction. Myocardial infarction is a large scale myocardial necrosis caused by the interruption of coronary artery blood supply, resulting in continuous ischemia in the blood supply area. It manifests as severe and longer-lasting retrosternal pain, which cannot be completely relieved by nitrate preparation or rest, and can be complicated by arrhythmia, shock or heart failure. According to the scope and depth of myocardial infarction, it can be divided into two main types: subendocardial infarction and transmural myocardial infarction, of which transmural myocardial infarction in particular can be complicated by heart failure, heart rupture, ventricular wall tumor, appendage thrombosis, cardiogenic shock, acute pericarditis or arrhythmia, etc. 3. Myocardial fibrosis. Myocardial fibrosis is the result of persistent and/or repeatedly aggravated ischemia and hypoxia of myocardial fibers caused by moderate to severe atherosclerotic stenosis of the coronary arteries. At this time, the heart volume may increase and the heart chambers dilate. 4. Sudden coronary death. Sudden coronary artery death is the most common type of sudden cardiac death. It is mostly seen in adults aged 40-50 years old, and is 3.9 times more common in men than in women. Sudden death is a sudden death that occurs naturally and unexpectedly. Sudden coronary death can occur after certain triggers, such as alcohol consumption, exertion, smoking and exercise, and the patient suddenly faints, has twitching of the limbs, urinary incontinence, or suddenly develops respiratory distress, foams at the mouth and rapidly falls into a coma. Death may occur immediately or one to several hours later, or in some cases during sleep at night. Risk factors for coronary heart attack Age (>65 years), hypercholesterolemia, atherosclerosis, lack of exercise and physical activity, smoking, hypertension, obesity, diabetes mellitus, family history of heart disease.