A hole in the wall between the heart's upper chambers that's present at birth.

An atrial septal defect (ASD) is a heart condition present at birth. That means it's a congenital heart defect. People with an ASD have a hole between the upper chambers of the heart. The hole increases the amount of blood going through the lungs.

Some atrial septal defects don't cause symptoms. A small one may be found by chance. But a large one that lasts a long time can damage the heart and lungs. Symptoms may include shortness of breath, a pounding, racing or skipping heartbeat, tiredness, and swelling in the legs, feet or belly.

Small atrial septal defects may close on their own. Surgery may be needed to repair an ASD that is large or that persists to prevent complications.