Ebstein’s Anomaly. Symptoms, Diagnosis, and Treatment

Ebstein’s anomaly is a rare genetic disease in which the valve between the two chambers on the right side of the heart is malformed. Two of the three valve cusps in the tricuspid valve are lower than usual, and the third one may be too long or attached to the heart wall.

Blood can leak backward into the top chamber of the heart (right tricuspid regurgitation), increasing the workload and decreasing the effectiveness of the heart in pumping blood into the lungs. This can lead to right-sided heart enlargement and heart failure.

In extreme cases, the right ventricle may be too small to pump enough blood to the lungs, and the blood backs up, or the lack of oxygenated blood pumped to the body can cause cyanosis (a bluish hue to the lips, nail beds, or skin).

Ebstein’s anomaly accounts for less than 1% of all congenital heart defects.

Normal heart function

A healthy heart has four distinct chambers, two on top called the atria, and two on the bottom called the ventricles. Valves sit between the top and bottom chambers on each side, preventing blood from flowing in the wrong direction through the heart.

1. Oxygen-depleted blood returns from the body and enters the heart's right atrium.
2. It passes through the tricuspid valve and into the right ventricle.
3. The right ventricle pumps the blood into the lungs, where it picks up oxygen.
4. The freshly oxygenated blood enters the left atrium of the heart.
5. It passes through the bicuspid valve (mitral valve) and into the left ventricle.
6. The left ventricle pumps oxygen-rich blood throughout the body.
7. Oxygen-depleted blood returns to the right ventricle to begin the cycle again.

Oxygen-rich blood and oxygen-depleted blood never mix, and the valves between the chambers prevent blood from returning to the previous chamber.

The defect

In Ebstein's anomaly, the tricuspid valve between the right atrium and the right ventricle is malformed. Two of the three valve cusps sit lower than usual in the ventricle, and one is too long or stuck to the heart wall. As a result, the valve does not close correctly, and blood flows back into the atria.

The extra blood increases the workload of the atrium, leading to heart enlargement, weakening, and failure.

The valve location and malformation vary from person to person, and the severity ranges from critical to virtually no symptoms at all. Infants and children are more likely to experience severe symptoms. If symptoms first appear in adulthood, they are usually relatively mild.

It is common for an atrial septal defect (ASD) to be present with an Ebstein's anomaly. An ASD is a hole between the right and left atria. This hole allows oxygen-rich and oxygen-depleted blood to mix in the two chambers, and some oxygen-depleted blood returns to the body.

If the tricuspid valve leak (regurgitation) is severe enough, or if the right ventricle is too small to pump sufficient blood to the lungs, a significant amount of oxygen-depleted blood will return to the body through the hole in the middle of the atria. The oxygen-depleted blood will cause low oxygen levels (saturation) in the body and cyanosis.

Aside from an ASD, other heart defects may also occur with Ebstein's anomaly.

Causes

Ebstein's anomaly is a genetic congenital heart defect (CHD) developed while a baby is developing before birth. If people in your family have a history of heart defects, you or your child have a higher risk of developing the condition.

The mother's use of certain medications, such as lithium (a mood-stabilizing drug), may also increase a child's risk of developing this CHD.

Symptoms

Symptoms of Ebstein's anomaly can range from mild to severe depending on the location of the valve, the severity of the defect, and if there are any other associated heart defects.

Symptoms may include:

• Fatigue.
• Cyanosis.
• Heart failure.
• Decreased stamina.
• Fluid retention (swelling in the legs and abdomen).

Ebstein's anomaly can also cause supraventricular tachycardia (an extremely fast heart rate) or some other heart arrhythmia, which can lead to symptoms such as:

• Fainting.
• Dizziness.
• Lightheadedness.
• Heart palpitations.
• Chest discomfort or pain.
• Shortness of breath with exertion.

Symptoms that do not develop until adulthood are usually less severe.

Infants cannot explain their symptoms, so they may express their discomfort by being unusually fussy. Infants may also have difficulty gaining weight.

Diagnosis

Even before symptoms start, your doctor or pediatrician may hear abnormal heart sounds during a physical exam. They may want to do some tests and scans to diagnose the condition further if they are concerned. These tests may include:

• Echocardiogram.
• EKG or ECG.
• Holter Monitor.
• Chest x-ray.
• Cardiac MRI.
• Pulse oximetry.
• Exercise stress test.
• Electrophysiology study.
• Cardiac catheterization.

Treatment

Treatment depends on the severity of the defect and the symptoms.

Follow-up appointments to monitor the heart and blood flow may be the only thing necessary, or your doctor may order medication to control the heart's rate or rhythm, reduce the heart's workload, or prevent blood clots.

Infants may receive a medication called nitrous oxide to increase blood flow to the lungs.

Mild tricuspid valve anomalies rarely need surgery.

Moderate to severe defects may need one or more surgeries if they affect quality of life, the heart is enlarging, the heart's workload is increasing, or heart function is decreasing.

Repairing the tricuspid valve cannot make it normal, but it can reduce the amount of blood regurgitation. In addition, the surgeon may be able to fix the atrial septal defect and any arrhythmias during the same surgery.

If the valve repair is inadequate, valve replacement may be necessary; in extreme cases, a heart transplant may be necessary.

Frequent follow-ups with a cardiologist or pediatric cardiologist to monitor the heart's function are essential. You or your child will usually be able to participate in sports, but your doctor may recommend you avoid certain intense competitive sports, such as football. Talk to your doctor about your activity level and in which sports you can safely participate.

You may need antibiotics before specific dental procedures if you are cyanotic or have had an artificial valve replacement.

Complications

If left untreated, Ebstein's anomaly can lead to heart failure, sudden cardiac arrest, and stroke.

After treatment or surgery, children generally do very well. However, if complications do arise, it is usually early.

Regardless, you or your child will need life-long check-ups with a cardiologist to monitor your heart function.