Endocardial Cushion Defect

What is an endocardial cushion defect?

Endocardial cushion defect is also called atrioventricular septal defect (AVSD). AVSD involves problems with the structure of the heart. The heart normally has 2 upper chambers (atria) and 2 lower chambers (ventricles). A normal heart also has 2 heart valves (the tricuspid and mitral valves) that separate the upper and lower chambers.

In AVSD, there may be a large hole in the center of the heart where the wall (septum) joins the upper and lower chambers of the heart. The tricuspid and mitral valves may not be separate. Instead, there can be one large valve between the upper and lower chambers of the heart (common atrioventricular valve).

The large opening in the center of the heart allows the oxygen-rich (red) and the oxygen-poor (blue) blood to mix. The heart pumps blood in a way that is not efficient and becomes enlarged.

How does it occur?

AVSD is the result of a problem with heart development before birth. The cause is unknown, although it is commonly found in infants with Down syndrome.

What are the symptoms?

The symptoms may begin at any time from birth to several months after birth. Most babies with this defect do not eat well. They are often undernourished and grow poorly. They breathe rapidly. They often have colds and may develop pneumonia. They may sweat and be clammy. They usually have a heart murmur.

How is it diagnosed?

Children with AVSD have enlarged hearts. The enlargement can be seen a chest X-ray or electrocardiogram (EKG), which is a recording of the electrical activity of the heart. The baby may have an echocardiogram, which uses sound waves to make pictures of the heart. Cardiac catheterization may also be done. In this procedure, a small tube is placed in the artery of the leg, a special dye is inserted, and X-ray pictures are taken of the heart.

How is it treated?

Surgery is used to repair the defect. The surgeon will close the holes between the upper and lower heart chambers and rebuild the tricuspid and mitral valves. Sometimes, however, the valves are too small or the valves allow blood to leak backward. If the valves do not work properly after surgery, the surgeon may have to operate again to fix them.

In rare cases, the defect is too complex to make all the repairs at one time. In such cases, the surgeon may place a pulmonary artery band, around the lung artery. The band narrows the artery and reduces blood flow to the lungs. When the child is older, the pulmonary artery band can be removed, and corrective surgery done.

What to expect after surgery

A cardiologist will examine your child from time to time after the surgery. Children with AVSD are at risk for getting an infection of the heart after dental work and certain other procedures. They must take antibiotics before such procedures are done.