The common left-to-right shunt type of congenital heart disease includes atrial septal defect, ventricular septal defect and arteriovenous ductus arteriosus, etc. For left-to-right shunt type, where left refers to artery and right refers to vein, left-to-right shunt means artery to vein shunt, as follows: 1. Atrial septal defect is a congenital defect between left atrium and right atrium, arterial blood from left atrium will shunt to venous blood from right atrium. 2. Ventricular septal defect is a congenital defect between the left and right ventricles, and the arterial blood from the left ventricle will shunt into the venous blood of the right ventricle. 3. Ductus arteriosus is a congenital channel between the pulmonary artery and the aorta, and a left-to-right shunt means that the blood from the aorta will shunt into the pulmonary artery.