A significant ASD is more than 1 cm in diameter, however, if there are symptoms such as shortness of breath, chest pain, etc. associated with ASD then intervention would be appropriate. .
The intervention for a 1 cm hole does not require surgery. The procedure involves a patch folded into a special catheter. he special catheter is inserted into a vein in the leg and advanced into the heart and through the hole. When the device is in proper position, the device is slowly pushed out the catheter until the discs of the device sit on each side of the hole (like a sandwich). Over time, heart tissue grows over the implant, becoming part of the heart.
The procedure is of very little risk, and the outcome is almost always a successful patch of the hole.