An atrial septal defect is a common form of congenital heart disease (a birth defect). The two upper chambers of the heart are called the atria. An atrial septal defect is an unnatural opening in the wall of between these two atria.

This opening (hole) can be closed with a patch graft or the opening can be sewn together. If a patch graft is used is is usually made of synthetic material or from a piece of pericardium (sac around the heart).

Acknowledgements
Content: Jaelene K. Williams, RN, MS
Medical Illustrations: Kathleen Wagner
Illustrations: Catherine Gendron