Although other tests such as electrocardiograms can diagnose coronary artery disease, they are sometimes inaccurate. The most accurate method of diagnosing coronary artery disease is coronary angiography. Coronary angiography is a minimally invasive and routine test that involves puncturing the femoral artery in the thigh or radial artery in the wrist, inserting a catheter to the root of the aorta, selectively feeding the catheter into the opening of the left and right coronary arteries, injecting contrast into the coronary arteries from the catheter, and performing X-ray cinematography or magnetic tape recording at the same time as the contrast is injected. In this way, the lumen of the entire left or right coronary artery and its branches can be clearly displayed, so that the presence or absence of stenosis and coronary lesions can be understood, and a clear diagnosis can be made of the location, extent, severity, and condition of the vessel wall. When the degree of coronary artery stenosis is ≥50%, the clinical diagnosis is coronary heart disease. When the stenosis is <50%, the diagnosis is coronary atherosclerosis. The physician can also perform left ventriculography to further understand the function of the left ventricle and the presence of ventricular wall tumors. This is a safe and reliable invasive diagnostic technique, and is the only diagnostic method that can directly observe the morphology of coronary arteries, and is considered the "gold standard" for the diagnosis of coronary artery disease, and can guide the measures to be taken for further treatment. Patients with mild coronary artery stenosis and good drug therapy should be treated mainly with drugs; patients with heavy symptoms, frequent attacks, severe coronary artery stenosis (more than 70%), or patients with myocardial infarction caused by blockage of blood vessels at the beginning of the disease, it is more difficult to control with drugs and should receive interventional treatment or surgical bypass surgery to open blood vessels. This technique requires short operation time and no obvious pain for the patient, and the patient can resume normal activities after resting for about one day after the operation. This examination should be done for patients with repeated chest pains that cannot be diagnosed but cannot exclude coronary artery disease, or for patients with myocardial ischemia or unexplained intractable arrhythmia or heart failure as suggested by electrocardiogram and other non-invasive tests, or for older patients who should receive this examination before undergoing cardiac surgery. Warm tip: The clinical manifestations of coronary heart disease often include angina pectoris, myocardial infarction, arrhythmia, heart failure and even cardiac arrest. Due to the lack of awareness and fear of coronary angiography, the degree of popularity is not high, and the clinical diagnosis of coronary heart disease is mostly inferred from clinical performance, which is more subjective and less accurate, even for those patients who have panic, chest pain, chest and back pain or combined with hypertension and diabetes, the patient is easily put on "coronary heart disease" without doing the corresponding examination. "This is extremely unscientific, and the use of medication is not based on the requirements of today's evidence-based medical development.