Ebstein's anomaly is a defect of the heart that occurs early in fetal life when the right pumping chamber (ventricle) and the valve (tricuspid valve) in that chamber do not correctly form during fetal life, for an unknown reasons. This tricuspid valve is abnormally located low in the right atrium, and it may not have a normal structure or function effectively. The right atrium is larger than typical and has thinner walls, and the right ventricle is smaller than usual.
Some children have this condition diagnosed as infants, and in other children it is not detected until they are adolescents or even adults. Ebstein's anomaly may be very mild, causing no symptoms and needing no treatment. If it is more severe, there may be blockage of blood flow to the pulmonary artery, the large vessel that leaves the right side of the heart to take blood to the lungs to be oxygenated. A blockage can cause the child's blood to have lower than a normal oxygen level, in which case the child's skin will have a grayish-blue color, especially around the mouth and nose (called cyanosis).
Ebstein's anomaly is quite rare, occurring in about 1 in 200,000 live births. It seems to occur as frequently in boys as in girls.
Common Associated Conditions
In 90% of children with Ebstein's anomaly, there is also a hole between the 2 upper chambers of the heart (an atrial-septal defect, or ASD). They may have rapid and unusual heartbeats (called atrial flutter or supraventricular tachycardia). About 10-25% of children with the condition will also have a condition called Wolff-Parkinson-White (WPW) syndrome, where there are extra nerve fibers in the heart that cause the heart muscle to receive extra signals to contract. Children with this condition can experience periodic episodes of very fast heart rate (perhaps 200-250 times per minute). Children with WPW syndrome can be at risk for sudden death.
Short-term Treatment and Outcomes
Many children with Ebstein's anomaly will have no symptoms, so no treatment will be necessary. If the valve is leaking or is narrowed, symptoms will make treatment necessary. Children may first be treated with drugs such as digoxin to strengthen the heart muscle's effectiveness and diuretics to remove excess fluid from the body and reduce the load on the heart.
Surgery is sometimes necessary either to repair or to replace the tricuspid heart valve so that blood flows readily to the lungs to receive oxygen. The hole between the upper chambers (the ASD) will also be repaired at the same time. Sometimes children who also have WPW syndrome will require surgery to improve the heart rate and rhythm; the surgery is called an called an oblation procedure, and extra nerve fibers in the heart will be destroyed so that the heart muscle receives only the appropriate signals to contract.
Long-term Treatment and Outcomes
Long-term, children with Ebstein's anomaly will need to be followed at least yearly by a cardiologist to be sure that there are no new symptoms that require treatment. Chest x-rays, electrocardiograms and echocardiograms are typical tests that will be periodically necessary. If an abnormal heart rate or rhythm is suspected, Holter monitoring will be done to record the heart beats for a period of time.
Individuals with this condition will require antibiotics when they have dental procedures throughout life because mouth bacteria can be released into the blood stream and set up an infection in the heart (endocarditis) when there is an abnormality in a heart wall or vessel.
Complications of Ebstein's anomaly include cardiomegaly (heart enlargement), heart failure (backflow of blood from a weak pumping action of the heart), cyanosis (lack of oxygen in the blood), and atrial or ventricular fibrillation (rapid heart rate). Some children have very mild Ebstein's anomaly and have no symptoms or complications.
If children have a hole between the atria (ASD), which most all do, and also have considerable blockage of the blood flow to the lungs, they may develop a right to left shunt through the ASD. Blood that lacks oxygen will flow from the body through the right atrium, through the ASD to the left side of the heart and back out to the body without being oxygenated. Children will be bluish-grey in color (cyanotic) if this occurs, and prompt treatment will be necessary as they will be fatigued and will grow more slowly.
Implications for Children's Development
Effects on a child's development will vary from none to considerable, depending on the condition's severity. Children with WPW syndrome might be a real risk for sudden death and once this is diagnosed they will require restricted physical activity until the oblation procedure is done. Once surgically treated, the child will not have activity restriction as long as the heart is functioning well, and their development will typically proceed normally. They may be restricted from competitive sports but allowed to participate in gym class to the extent that they can tolerate. Children should be allowed to regulate themselves in terms of how much activity they can tolerate, and if they become fatigued they should be permitted to rest. However, the family should encourage the child to be active, independent and self-confident, within the limits that are realistic for their condition.
For more information, including resources for parents and general information about congenital cardiac conditions, visit the following websites:
- CDC Congenital Heart Defects Information
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