First, what is coronary heart disease coronary heart disease is a kind of coronary artery organic stenosis or obstruction caused by myocardial ischemia and hypoxia (angina pectoris) or myocardial necrosis (myocardial infarction) heart disease, also known as ischemic heart disease. Angina pectoris is a clinical syndrome caused by insufficient blood supply to the coronary arteries and acute and temporary ischemia and hypoxia of the myocardium. Second, the clinical type of coronary heart disease and performance According to the World Health Organization (WHO) typing standards, the clinical type of coronary heart disease can be divided into three types: angina pectoris, myocardial infarction and sudden death. Angina pectoris can be further divided into exertional angina and spontaneous angina. 1, exertional angina is subdivided into 3 categories: new-onset angina, stable exertional angina, and worsening exertional angina. 2.Spontaneous angina generally refers to angina that occurs at rest, the pain is long and severe, and is not easily relieved by nitroglycerin. Angina pectoris is the most common type of coronary heart disease, typical angina attack is a sudden onset of the upper or middle part of the sternum, crushing, stuffy or suffocating pain, can also affect most of the precordial area, some patients feel to the left shoulder, left upper limb, neck, throat radiation. Rest or oral nitroglycerin pain can be relieved. Third, what are the methods of diagnosing coronary heart disease? 1, clinical manifestations: angina pectoris is the main clinical symptom of coronary heart disease, typical symptoms and signs of coronary heart disease angina pectoris and myocardial infarction diagnosis is crucial. 2, electrocardiogram: electrocardiogram is the earliest, most commonly used and most basic diagnostic method in the diagnosis of coronary heart disease. Coronary angiography: It is the “gold standard” for the diagnosis of coronary heart disease. It can clarify whether the coronary arteries are stenotic, the location, degree and scope of stenosis, etc., and can guide the measures to be taken for further treatment accordingly. Combined with left heart imaging, cardiac function can be evaluated.