For the classification of congenital heart disease, we often classify congenital heart disease into three major categories according to the location of the malformation, whether there is a direct shunt between the right heart cavity and the left heart cavity and large blood vessels: the first category is right-to-left shunt type, also called cyanotic congenital disease, this category is due to the structural abnormality of the heart that causes the pressure in the right heart to exceed that in the left heart, so that the blood flows from right to left or the origin of the large arteries is abnormal, which will This type of disease is caused by structural anomalies in the heart that cause the pressure in the right heart to exceed that in the left heart, causing the blood to flow from the right to the left or the origin of the great arteries to be abnormal. The second type is the left-to-right shunt type, this includes atrial septal defect, ventricular septal defect or patent ductus arteriosus. Under normal circumstances, blood is shunted from left to right. When seen in severe crying or pathological conditions, right-to-left shunts also occur when the pulmonary artery and right ventricular pressure have to exceed that of the left ventricle, so this type is also called latent cyanotic precordial disease. The third type is the type without shunts, which refers to the absence of abnormal pathways or shunts between the left and right sides of the heart or between the arteries and veins, such as aortic constriction and pulmonary artery constriction, etc. This is the type of precordial disease without shunts.