Atrial septal defect

Alternative names:

ASD

Definition:

A congenital defect where the wall between the right and left atria does not close completely.

Causes, incidence, and risk factors:

Atrial septal defect (ASD) is a congenital heart defect. In fetal circulation there is normally an opening between the atria (the upper chambers of the heart) to allow blood to bypass the lungs. This opening usually closes about the time the baby is born. If the ASD is persistant, there is continuation of the opening between the left and right atria.

ASD is present in 4 out of 100,000 people. Symptoms are usually absent if other defects are not present. If symptoms are present they usually manifest before age 30. Individuals with ASD are at an increased risk for developing bacterial endocarditis.