Secondary foramen ovale atrial septal defect is one kind of congenital heart disease, atrial septal defect, which produces discomfort symptoms mainly due to the inflow of blood from the left atrium into the right atrium. The inflow of blood from the left atrium into the right atrium in atrial septal defect will cause the pressure of pulmonary circulation to rise, which will not tolerate the oxygen consumption after activity, and then can lead to shortness of breath, cough and other pulmonary discomfort symptoms; 2. Cyanosis: Severe pulmonary hypertension occurs in the late stage of atrial septal defect, causing right-to-left shunt, resulting in reduced pulmonary blood circulation and cyanosis, suggesting severe hypoxia.