Let’s first look at what coronary heart disease is. Coronary heart disease (CHD) is the abbreviation of coronary artery heart disease, which refers to the myocardial dysfunction and/or organic lesion caused by the narrowing of coronary arteries and insufficient blood supply, so it is also called ischemic heart disease. The occurrence of coronary heart disease is closely related to the degree of atherosclerotic stenosis of the coronary arteries, while suffering from diseases such as hypertension and diabetes, as well as excessive obesity and poor lifestyle habits are the main factors triggering the disease. Coronary heart disease is one of the diseases with the highest mortality rate in the world, and according to a 2011 report by the World Health Organization, China has the second highest number of coronary heart disease deaths in the world. Coronary heart disease is divided into five major types: 1, asymptomatic coronary heart disease Many patients have extensive coronary artery blockage but have not felt angina, and some patients do not even feel angina when myocardial infarction. These patients have the same chance of sudden cardiac death and myocardial infarction as patients with angina, so attention should be paid to the usual heart care. 2, angina pectoris type coronary heart disease manifested as the pressure behind the sternum, stuffy feeling, accompanied by obvious anxiety, lasting 3 to 5 minutes, often spread to the left side of the arm, shoulder, jaw, throat, back, sometimes can involve these parts without affecting the posterior sternal area, exertion, emotional excitement, cold, full meals and other conditions that increase myocardial oxygen consumption is called exertional angina, rest and nitroglycerin relief. Stable angina is divided into stable and unstable angina. Unstable angina is the precursor of acute myocardial infarction, once found should immediately go to the hospital. 3, myocardial infarction type coronary heart disease manifested as persistent severe pressure, stuffy feeling, or even knife-like pain, located behind the sternum, often spread to the whole forehead, with the left side being heavier. The pain site is the same as the previous angina site, but it lasts longer and is more severe, and cannot be relieved by rest or nitroglycerin. This condition should be seen immediately. 4, ischemic cardiomyopathy type coronary artery disease Some patients with original angina attack, later due to extensive lesions, extensive myocardial fibrosis, the performance of heart failure, such as shortness of breath, edema, weakness, etc., and a variety of arrhythmias, manifested as palpitations, and some patients have never had angina, but directly manifested as heart failure and arrhythmias. Therefore, exertional dyspnea is often due to heart failure, and it is recommended to see the cardiovascular department for unexplained dyspnea. 5, sudden death coronary heart disease refers to the sudden and unpredictable death caused by coronary heart disease, caused by cardiac arrest within 6 hours after the appearance of acute symptoms. It is mainly caused by abnormal electrophysiological activity of myocardial cells due to ischemia, and severe arrhythmia occurs. How is coronary heart disease diagnosed? 1. It mainly includes symptoms and signs. Angina pectoris is the main clinical symptom of coronary artery disease. According to the characteristics of angina pectoris such as location, nature, trigger, duration and relief mode, and the accompanying symptoms and signs, it is possible to distinguish angina pectoris from myocardial infarction, and it can be said that typical symptoms and signs are essential for the diagnosis of coronary angina pectoris and myocardial infarction. 2, electrocardiogram: electrocardiogram is the earliest, most commonly used and most basic diagnostic method in the diagnosis of coronary heart disease. When the patient’s condition changes, the changes can be captured in time, and continuous dynamic observation and various load tests can be performed to improve its diagnostic sensitivity. 3.Coronary angiography: It is the “gold standard” of coronary artery disease diagnosis. It can clarify the presence or absence of coronary artery stenosis, the site, degree and scope of stenosis, and guide the measures to be taken for further treatment accordingly. 4. Myocardial enzymatic examination: It is one of the important tools for the diagnosis and differential diagnosis of acute myocardial infarction. The diagnosis of acute myocardial infarction can be clearly made clinically based on the sequence changes of serum enzyme concentration and the elevation of specific isoenzymes and other affirmative enzymatic changes. Should I do angiography or cardiac CT? Indications for coronary angiography: divided into two categories: The first category is unclear clinical diagnosis of coronary heart disease, mainly for diagnostic purposes, including the following; 1, unexplained chest pain, non-invasive tests can not confirm the diagnosis, clinical suspicion of coronary heart disease, the need for treatment according to coronary heart disease. 2, unexplained arrhythmias, such as intractable ventricular arrhythmias and conduction block; sometimes coronary angiography is required to exclude coronary artery disease. 3, unexplained left heart insufficiency, mainly seen in dilated cardiomyopathy or ischemic cardiomyopathy, the identification of the two often requires coronary angiography. 4.Precardiac disease and valvular disease before surgery, age > 40 years, easily combined with malformations of coronary arteries or atherosclerosis, can be intervened at the same time of surgery. 5.Asymptomatic but suspected coronary artery disease in high-risk occupations such as pilots, car drivers, police officers, athletes, firefighters, etc. or medical insurance needs. The second major category is mainly for therapeutic purposes, the clinical diagnosis of coronary heart disease is clear, coronary angiography is performed to further clarify the extent of coronary lesions, the degree, to choose the treatment plan, mainly including the following; 1, stable angina, the effect of medical treatment is poor, affecting work and life; 2, unstable angina, first take medical active intensive treatment, once the condition is stable, active coronary artery 3, acute myocardial infarction, the main treatment of acute myocardial infarction is reperfusion therapy of occluded vessels, PCI technology with its high success rate and reliable effect has been used as the preferred method of reperfusion therapy of acute myocardial infarction. 4.Asymptomatic coronary artery disease, in which coronary angiography should be performed for patients with positive exercise test with obvious risk factors. 5.Primary cardiac arrest resuscitated successfully, with a higher likelihood of left main stem lesion or proximal anterior descending branch lesion, is a high-risk group and should be treated with early vascular lesion intervention, requiring coronary artery evaluation. 6. After bypass surgery or PTCA, angina recurs and often requires coronary artery lesion evaluation again. Any dose of radiation can increase the risk of distant cancer, which means there is no so-called threshold value. It takes a long development process for radiation exposure to cause cancer, and its cumulative effect can increase the risk of disease afterwards, so we suggest that for the health of patients, do not abuse the means of examination, and do not perform unnecessary examination unless it is necessary.