In fetal circulation, there is normally an opening between the two atria (the upper chambers of the heart) to allow blood to bypass the lungs. This opening usually closes around the time the baby is born.
If the ASD is persistent, blood continues to flow from the left to the right atria. This is called a shunt. If too much blood moves to the right side of the heart, pressures in the lungs build up. The shunt can be reversed so that blood flows from right to left. Many problems can occur if the shunt is large, but small atrial septal defects often cause very few issues and maybe found much later in life.
ASD is not very common. When the person has no other congenital disability, symptoms may be absent, particularly in children. Symptoms may begin any time after birth through childhood. Individuals with ASD are at an increased risk for developing several complications, including:
- Atrial fibrillation (in adults)
- Heart failure
- Pulmonary over circulation
- Pulmonary hypertension
- Stroke