An atrial septal defect (ASD) is a hole in the part of the septum that separates the atria (upper chambers of the heart). This heart defect allows oxygen-rich blood from the left atrium to flow across the atrial septum into the right atrium instead of flowing down to the left ventricle as it should. This is inefficient because oxygen-rich blood gets pumped back to the lungs, where it has just been, instead of going to the body.
An ASD can be small or large. Small ASDs allow only a little blood to flow from one atrium to the other. Small ASDs don't affect the way the heart works and therefore don't need any special treatment. Many small ASDs close on their own as the heart grows during childhood.
Medium to large ASDs allow more blood to leak from one atrium to the other, and they are less likely to close on their own. Most children with ASDs have no symptoms, even if they have large ASDs.
There are three major types of ASD:
Over time, the extra blood flow to the right side of the heart and the lungs may cause problems for a heart that has an ASD. Usually, most of these problems don’t show up until adulthood, often around age 30 or later. They are rare in infants and children. These possible problems include:
These problems develop over many years and don’t occur in children. They also are rare in adults because most ASDs either close on their own or are repaired in early childhood.
A ventricular septal defect (VSD) is a hole in the part of the septum that separates the ventricles, the lower chambers of the heart. The hole allows oxygen-rich blood to flow from the left ventricle across the heart into the right ventricle instead of flowing up into the aorta and out to the body as it should.
An infant born with a VSD may have a single hole or more than one hole in the wall that separates the two ventricles. The defect also may occur by itself or with other congenital heart defects.
Doctors classify VSDs based on the:
VSDs can be small or large. A small VSD doesn’t cause problems and may often close on its own. Because small VSDs allow only a small amount of blood to flow between the ventricles, they’re sometimes called restrictive VSDs. Small VSDs don’t cause any symptoms.
Medium VSDs are less likely than small defects to close on their own. They may require surgery to close and may cause symptoms during infancy and childhood.
Large VSDs allow a large amount of blood to flow from the left ventricle to the right ventricle and are sometimes called nonrestrictive VSDs. A large VSD is less likely to close completely on its own, but it may get smaller over time. Large VSDs often cause symptoms in infants and children, and surgery is usually needed to close them.
VSDs are found in different parts of the septum.
A moderate to large VSD can cause:
Author/Source: National Heart, Lung & Blood Institute, Division of the National Institutes of Health [NIH]
Retrieved: June 2008