An atrial septal defect (ASD) is a hole in the wall that separates the atria (the smaller upper chambers) of the heart. The wall that separates the chambers is called the septum. The hole can make the right side of the heart work harder than usual.
In most cases, there is no clear cause of an ASD. ASDs often happen at random. It is not anyone’s fault.
The ASD allows for extra blood flow to the lungs. In most cases, there may be no symptoms. But the extra blood flow can damage the lungs and make the heart grow larger than usual.
If left untreated, lung damage can become permanent and life-threatening. Some children can also develop pneumonia (build-up of fluid in the lungs) or have asthma-like breathing problems.
There are 4 types of ASD. Some of these defects can involve other heart structures:
Most babies and children who have an ASD might not have any symptoms. In fact, many babies grow normally.
In others, common symptoms of ASDs include: