Ebstein's anomaly

Definition

Ebstein's anomaly is a rare heart defect in which parts of the tricuspid valve are abnormal. The tricuspid valve separates the right lower heart chamber (right ventricle) from the right upper heart chamber (right atrium).

The condition is congenital, which means it is present from birth.

See also:

• Atrial septal defect
• Congenital heart disease

Alternative Names

Ebstein's malformation

Causes, incidence, and risk factors

The tricuspid valve is normally made of three parts, called leaflets or flaps. The leaflets open to allow blood to move from the right atrium (top chamber) to the right ventricle (bottom chamber) while the heart relaxes. They close to prevent blood from moving from the right ventricle to the right atrium while the heart pumps.

In persons with Ebstein's anomaly, the leaflets are unusually deep in the right ventricle. The leaflets are often larger than normal. The defect usually causes the valve to work poorly, and blood may go the wrong way back into the right atrium. The backup of blood flow can lead to heart swelling and fluid buildup in the lungs or liver. Sometimes, blood can't get out of the heart into the lungs and the person may appear blue.

In most cases, patients also have a hole in the wall separating the heart's two upper chambers and blood flow across this hole may cause oxygen-poor blood to go to the body. There may be narrowing of the valve that leads to the lungs (pulmonary valve).

Ebstein's anomaly occurs as a baby develops in the womb. The exact cause is unknown, although the use of certain drugs (such as lithium or benzodiazepines) during pregnancy may play a role. The condition is rare. It is more common in white people.

Symptoms

Symptoms range from mild to very severe. Often, symptoms develop soon after birth and include bluish-colored lips and nails due to low blood oxygen levels. In severe cases, the baby appears very sick and has trouble breathing.

Symptoms in older children may include:

• Cough
• Failure to grow
• Fatigue
• Rapid breathing
• Shortness of breath
• Very fast heartbeat

Signs and tests

Newborns who have a severe leakage across the tricuspid valve will have very low levels of oxygen in their blood and significant heart swelling. The doctor may hear abnormal heart sounds, such as murmur, when listening to the chest with a stethoscope.

Tests that can help diagnose this condition include:

• Chest x-ray
• Magnetic resonance imaging (MRI) of the heart
• Measurement of the electrical activity of the heart (EKG)
• Ultrasound of the heart (echocardiogram)

Treatment

Treatment depends on the severity of the defect and the specific symptoms. Medical care may include:

• Medications to help with heart failure
• Oxygen and other breathing support
• Surgery to correct the valve may be needed for children who continue to worsen or who have more serious complications

Support Groups

Expectations (prognosis)

In general, the earlier symptoms develop, the more severe the disease.

Some patients may have either no symptoms or very mild symptoms. Others may worsen over time, developing blue coloring (cyanosis), heart failure, heart block, or dangerous heart rhythms.

Complications

A severe leakage can lead to swelling of the heart and liver, and congestive heart failure.

Other complications may include:

• Abnormal heart rhythms (arrhythmias), including abormally fast rhythms (tachyarrhythmias) and abnormally slow rhythms (bradyarrhythmias and heart block)
• Blood clots from the heart to other parts of the body
• Brain abscess

Calling your health care provider

Call your health care provider if your child develops symptoms of this condition. Seek immediate medical attention if breathing problems occur.

Prevention

There is no known prevention, other than talking with your doctor before a pregnancy if you are taking medicines that are thought to be related to developing this disease. You may be able to prevent some of the complications of the disease. For example, taking antibiotics before dental surgery may help prevent endocarditis.

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References

Cyanotic Congenital Heart Defects. In: Park MK, Troxler RG, eds. Pediatric Cardiology for Practioners. 5th ed. St. Louis, Mo: Mosby, Inc; 2008: chap 14.