Atrial septal defect is a common congenital heart disease in childhood, and the incidence of this disease is still relatively high. Depending on the anatomical lesion, atrial septal defects are classified as foramen ovale nonocclusion, foramen ovale nonocclusion and foramen ovale nonocclusion. The second patent foramen ovale, also known as secondary patent foramen ovale, is located in the middle oval fossa of the interatrial septum or near the superior and inferior vena cava, and this type of defect can account for 75% of all septal defects and is relatively less severe. If the defect is about three millimeters in size, most cases have the potential to close spontaneously 5 to 7 months after birth, and even if it does not close spontaneously, intervention can be performed when the child is about 5 weeks old.