Ebstein's anomaly is a congenital downward displacement of the tricuspid valve (located between the heart's upper and lower chambers on the right side) into the heart's right bottom chamber (or right ventricle). The major problem with this abnormality is that the tricuspid valve may be leaky or regurgitant.
If it is very leaky, blood goes backward instead of forward into the pulmonary artery every time the right ventricle contracts because the resistance in the right atrium is usually lower than the lungs. The amount of leakiness varies from minimal to very severe. Mild abnormalities with minimal leakiness may not ever require any intervention. With severe leakiness, intervention may be required soon after birth.
With severe Ebstein's anomaly, the leaky valve causes the right atrium to become very large. In fact, the right atrium may take up a large portion of the chest so that there is no room for the lungs. Sometimes, this improves with time. If not, surgery may be recommended.
Heart with Ebstein's Anomaly
Very mild Ebstein's anomaly may cause no symptoms and be diagnosed only by the finding of an abnormal murmur on physical examination. People with more severe abnormalities may have symptoms that suggest a rhythm disturbance or difficulty with exercise due to the leakiness of the valve. With a very severe abnormality, the diagnosis is made soon after birth because many of these babies may be blue or have symptoms of heart failure.
In the beginning, medications may be given to try to reduce the pressure in the right ventricle so that less leakiness occurs. Sometimes, prostaglandin needs to be given to keep the ductus arteriosus (PDA) open until the pressure in the right ventricle gets lower. With a PDA, blood can still get to the lungs from the aorta if the right ventricle cannot pump blood to the lungs. Once the pressure in the lungs is lower, the right ventricle may be able to pump more blood to the lungs than leaks back across the tricuspid valve and the baby can survive. If this is not possible, heart surgery may be needed.
The options for a newborn infant are few. One is to try to repair the valve. Traditionally, this has not been very successful. Another option is to sew the valve shut so it doesn’t leak, and to perform a series of operations leading to a univentricular repair or Fontan operation. Sometimes there is a combination of approaches used. Another option is heart transplantation.
In an older child or adult, surgical operations to repair the valve have a higher success rate. There is also the possibility of replacing the valve with an artificial valve (not performed in babies because they will outgrow it too quickly).
The risks of open-heart surgery are bleeding, infection and the need for cardiopulmonary bypass. There is also the risk that the valve will remain leaky and require another operation. On the other hand, the valve may become obstructed or stenotic (the reverse of leakiness) if the repair makes the valve opening too small.
If the valve is not severely leaky at birth, but becomes leakier with time, alternative surgical operations are available that are not usually performed at birth. These include reconstruction or replacement of the tricuspid valve.
The outlook for this type of surgery is better in an infant, but still requires lifelong follow-up with the possibility of needing additional interventions. Lifestyle and lifespan depend on the severity of the leakiness and may be near normal if the leakiness is very mild.