What Causes Ebstein’s Anomaly?

Ebstein’s anomaly is a heart defect that arises early in fetal life when the right pumping chamber (ventricle) and valve (tricuspid valve) do not develop properly for unknown reasons.

With Ebstein’s anomaly, the tricuspid valve is located unusually low in the right atrium and may not have a normal structure or function properly. The right atrium is bigger and has thinner walls than usual, whereas the right ventricle is smaller than usual.

Some infants are diagnosed with this illness in the fetal stage, whereas others are not diagnosed until they are teens or even adults. In some cases, Ebstein’s anomaly could be so benign that it causes no symptoms and requires no treatment.

However, in severe cases, the condition can cause the blood flow to the pulmonary artery to be blocked. The pulmonary artery is the major vessel that leaves the right side of the heart to transport blood to the lungs for oxygenation. This blockage can cause the child's blood to have a lower-than-usual oxygen level, causing the skin to become gray-blue, especially around the mouth and nose (called cyanosis).

The symptoms of Ebstein’s anomaly range in severity. Symptoms of severe cases seen immediately after delivery may include:

• Pale lips and nails due to low blood oxygen
• Difficulty breathing

In older children, symptoms may include:

• Cough
• Poor weight gain
• Breathing difficulty
• Rapid pulse
• Generalized fatigue
• Swelling of the abdomen and legs
• Excessive sweating

Ebstein’s anomaly can lead to the following complications:

• Right atrial hypertrophy
• Arrhythmias (irregular cardiac rhythm)
• Bluish discoloration of the skin (when low-oxygen blood from the right atrial crosses into the left atrium, the red, oxygen-filled blood in the left atrium turns blue)
• Formation of blood clots in other parts of the body
• Brain abscess

In severe cases, pressure in the right atrium may force poorly oxygenated blood to flow to the left atrium through a tiny hole in the heart.

Ebstein's abnormality is sometimes discovered before birth during a fetal ultrasound.

If your newborn has a blue tinge to their skin at birth or the doctor detects a cardiac issue, you will be directed to a pediatric cardiologist for a physical exam. The doctor listens to the baby's heart and lungs and assesses the oxygen level in their blood (noninvasively).

To aid with the diagnosis, the doctor may order one or more of the following tests:

• Chest X-ray: Provided images of the structures inside the chest, including the lungs, heart, and chest wall (using low radiation)
• CT scan: Creates three-dimensional images of the heart and blood arteries using X-rays
• Electrocardiogram: Analyzes the electrical activity of the heart
• Echocardiography (a cardiac ultrasound): Creates images of the heart using high-frequency sound waves
• MRI of the heart: Uses radio waves, magnets, and computer technology to produce images of the heart and blood arteries
• Stress test: Evaluates how your heart performs during exercise; examples include treadmill or bike stress testing, nuclear stress tests, stress echocardiograms, and chemically induced stress tests
• Transesophageal echocardiogram: Captures highly comprehensive images of the heart using a probe inserted into the esophagus
• Cardiac catheterization: A minimally invasive procedure that involves inserting thin, flexible tubes called catheters into the blood channels to problem regions to diagnose and treat various heart and vascular diseases

The severity of the baby's symptoms determines the type and timing of postnatal therapy for Ebstein’s anomaly.

Because many children with Ebstein’s anomaly have no symptoms, no active treatment may not be required. Treatment is done only if the valve is leaky or constricted and is presented with other symptoms. 

Treatment may not be necessary for mild to moderate cases, but a pediatric cardiologist must monitor the child. In severe cases, medications and surgery may be required to repair the valve or allow the heart to bypass the valve and deliver blood to the lungs and other body parts.

Treatment options for Ebstein's anomaly generally include:

• Regular monitoring for symptoms of heart enlargement or weakness
• Medications for oxygen/breathing support
• Surgery to repair or replace the tricuspid valve (in rare cases, a series of surgical procedures may be required if the right ventricle is too small)
• Heart transplant as a last resort in severe cases

Surgical intervention improves the prognosis of the condition. Postoperatively, continuing periodic follow-ups in specialized clinics is advised.

Known cases of Ebstein’s anomaly must be observed by a cardiologist for at least a year to ensure that there are no new symptoms that require treatment. Chest X-rays, electrocardiograms, and echocardiograms are common tests that may be required regularly.

Individuals with this condition will need antibiotics for the rest of their lives because oral bacteria can enter the bloodstream and cause an infection in the heart (endocarditis) when there is an irregularity in a heart wall or channel.