Ebstein's anomaly

Ebstein anomaly is a congenital heart defect in which the opening of the tricuspid valve is displaced towards the apex of the right ventricle of the heart.

Causes 

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

The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. There is subsequent 'atrialization' of a portion of the morphologic right ventricle (which is then contiguous with the right atrium). This causes the right atrium to be large and the anatomic right ventricle to be small in size.

• S3 heart sound
• S4 heart sound
• Systolic murmur of tricuspid regurgitation
• Mid-diastolic murmur along the lower left sternal border
• Right atrial hypertrophy
• Right ventricular conduction defects
• Wolff-Parkinson-White syndrome often accompanies

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
  
  
  

  The Canadian Cardiovascular Society (CCS) recommends surgical intervention for the following indications:

  • Limited exercise capacity (NYHA III-IV).
  • Increasing heart size (cardiothoracic ratio greater than 65%).
  • Important cyanosis (resting oxygen saturation of less than 90%). (Level B)
  • Severe tricuspid regurgitation with symptoms.
  • Transient ischemic attack or stroke

  The CCS further recommends patients who require operation for Ebstein anomaly should be operated on by congenital heart surgeons who have substantial specific experience and success with this operation. Every effort should be made to preserve the native tricuspid valve.

  
  

  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

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.

References

1. Cyanotic Congenital Heart Defects. In: Park MK, Troxler RG, eds. Pediatric Cardiology for Practioners. 5th ed. St. Louis, Mo: Mosby, Inc; 2008: chap 14.
2. ^ ^a b Silversides, C. K.; Salehian, O.; Oechslin, E.; Schwerzmann, M.; Vonder Muhll, I.; Khairy, P.; Horlick, E.; Landzberg, M. et al. (2010). "Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: Complex congenital cardiac lesions". The Canadian journal of cardiology 26 (3): e98–117.