Atrial septal defects can actually be divided into two major categories, including primary and secondary foramen ovale septal defects. The atrial septal defect mentioned in the question is often secondary foramen ovale septal defect, which is divided into four categories: 1, central defect, the site of the defect is in the fossa ovalis, the fossa ovalis is open during the embryonic period, after birth, the fossa ovalis is closed, but some people continue to be absent, this time can be done to block the umbrella, the central defect is blocked, the treatment effect is better. 2, superior vena cava type defect, that is 3.Inferior cavity defect, like superior cavity defect, because there is no adequate border of the atrial septum, so the effect of blocking is poor, and most patients can only be treated by cardiac surgery. 4.Mixed type, that is, the above three mixed together, two or more, this is the atrial septal defect This is the type of septal defect.