Atrial Septal Defect (ASD)

This is a hole between the two receiving chambers which allows blood from the left side to pass back to the right side and into the lungs.

There are three types: the commonest is in the middle of the atrial septum (the secundum defect). Sometimes it is in the lower part of the septum (the primum defect) and is associated with an abnormality (often a leak) of the mitral valve. Occasionally, it is in the top of the septum (the sinus venosus defect) associated with an abnormality of the right upper lung vein.

Usually children have no symptoms, and a routine examination finds a murmur present Occasionally, there is poor weight gain and failure to thrive.

Small defects that allow little blood to shunt from one side of the heart to the other often cause no problems. Such defects in the middle portion of the septum may close spontaneously in young children.

Moderate and large defects do not close by themselves, and the extra work which has t be done by the heart over many years into adult life causes a strain on its right side, with enlargement of the receiving chamber and pump chamber. As a result, the heart gets tired in middle life. The result of repairing the defect at that age are not as good as when undertaken earlier. The plan, therefore is to close these defects during childhood.

Many which are in the mid portion of the atrial septum, have good margins, are free from adjacent structures and are not too large, can be closed by a plastic and metal device, or a plug inserted at cardiac catheterisation.

Asprin is given for three months following this to reduce chances of clots developing on the device. Antibiotic prophylaxis is needed for only one year assuming the hole is closed.

In others, the defect will be too large or adjacent to important structures. This needs to be closed by open heart surgery either by direct suture or with a patch. Antibiotic prophylaxis is not required beyond a year after closure.

secundum artial septal defect

Victoria & Tasmania