Ebstein’s anomaly is a rare heart defect that involves a deformed and misplaced tricuspid valve and usually occurs along with other heart defects. In a normal heart, the tricuspid valve is located between the right upper chamber (atrium) and the right lower chamber (ventricle). It opens and closes at precise intervals, allowing blood to travel from the right atrium to the right ventricle, which then pumps the blood to the lungs to pick up oxygen.
In Ebstein’s anomaly, however, the tricuspid valve droops into the right ventricle and cannot close properly. Alternatively, the condition may be associated with malformations in the shape of the right ventricle or right atrium. Any of these conditions means that the blood flow between the right atrium and right ventricle is irregular. Instead of flowing in only one direction, blood is allowed to flow backward from the right ventricle into the right atrium through the tricuspid valve. This is known as tricuspid regurgitation. Ebstein's anomaly is the most important cause of tricuspid regurgitation.
In addition to problems with the right-heart anatomy, patients with Ebstein’s anomaly also tend to have associated heart defects, including a patent foramen ovale or an atrial septal defect (ASD). The ASD is the more serious of the two. An ASD is a hole between the left and right atria that allows oxygen-poor blood from the right atrium to mix with oxygen-rich blood in the left atrium. Additionally, about 10 percent of patients also experience abnormal heart rhythms (arrhythmias).
As a result of the various abnormalities, less blood receives fresh oxygen, which leads to cyanosis – a bluish tint to the skin because the body is not receiving enough oxygen-rich blood (a condition often called blue baby in infants).
The range of problems associated with Ebstein’s anomaly depends on the severity of the condition. Severe Ebstein’s anomaly is a life-threatening condition that can progress to heart failure or death and must be treated immediately. A person with mild Ebstein’s anomaly might show no symptoms until adulthood, and then show only mild symptoms.
Treatment for Ebstein’s anomaly depends on the severity of the symptoms and the extent of anatomical abnormalities. Mild Ebstein’s may be treated with medication to relieve the symptoms. More serious Ebstein’s will usually require open-heart surgery, usually early in life. After surgery, lifelong medical follow-up and close medical management will be necessary. For example, patients will need to take antibiotics before any dental, medical or surgical procedure to prevent a potentially life-threatening infection called endocarditis.
However, in most adults with Ebstein’s anomaly the condition is mild and does not require surgery, according to the American Heart Association.
About Ebstein’s anomaly
First described in 1866, Ebstein’s anomaly is an uncommon heart condition that is present at birth (a congenital heart condition), in which the right side of the heart, especially the tricuspid valve, is abnormally formed. There are several characteristics that may be associated with Ebstein's anomaly:
A tricuspid valve that droops into the right lower chamber (ventricle) so the valve does not function properly.
An abnormally formed tricuspid valve that is too firmly attached to the ventricle wall and does not function properly.
The right ventricle is atrialized, or unusually thin and enlarged in the region of the tricuspid valve and does not pump adequately. At the same time, the right atrium and tricuspid valve may be enlarged.
The lower portion right ventricle may be unusually small, and there is an outflow obstruction that reduces the amount of blood that can flow from the chamber into the pulmonary arteries, which carry blood to the lungs.
These conditions may exist in various degrees among patients with Ebstein's anomaly. Their severity depends on the severity of symptoms and the need for treatment. Ebstein's anomaly is the most important congenital cause of tricuspid regurgitation, which occurs when oxygen-poor blood flows backward from the right ventricle into the right atrium. In very severe cases, the right ventricle is essentially non-functioning and greatly enlarged, which compromises the left ventricle also. This condition is a medical emergency that must be dealt with immediately after birth. In less severe cases, symptoms may not be apparent for many years and intervention is based on the severity of symptoms.
In addition to the leaky tricuspid valve, patients with Ebstein’s anomaly also tend to have associated heart defects, including a patent foramen ovale or atrial septal defect (ASD). The ASD is the more serious of the two. It is a hole between the left and right atria that allows oxygen-poor blood from the right atrium to mix with oxygen-rich blood in the left atrium. These two types of blood should always remain separate.
Other heart defects that are associated with Ebstein’s anomaly include a ventricular septal defect, patent ductus arteriosus, coarctation of the aorta or left ventricular cardiomyopathy.
Ebstein’s anomaly causes the heart to work harder to meet the body’s demand for oxygen-rich blood. As a result of the additional burden placed on the heart, any of the following complications could occur:
Enlarged heart and weakening of the heart muscle due to the additional strain placed on it.
Heart failure, if the heart continues to overexert itself without treatment.
An embolism, caused by blood clots that form in the veins. Blood clots can travel to the heart, get pumped out to the body, and become lodged in the blood vessels of a vital organ.
Abnormal heart rhythms (arrhythmia), caused when the heart defects block or divert electrical impulses from the normal pathways of the heart’s conduction system. Wolff-Parkinson White (WPW) syndrome can be associated with Ebstein’s anomaly. In this situation, patients can have an extra atrio-ventricular connection known as an accessory pathway that can result in different kinds of arrhythmias.
Ebstein’s anomaly is a rare condition, occurring in about 1 in 50,000 to 1 in 100,000 people. Males and females are equally affected, with the disease showing higher prevalence in whites. It is not believed that Ebstein’s is a genetic (and therefore inherited) disease. Studies show that most cases occur randomly, although a few cases have occurred within families.
Signs and symptoms of Ebstein's anomaly
The signs and symptoms of Ebstein’s anomaly depend on the severity of the condition. Among more severe cases, the skin may be slightly blue (cyanosis), a condition that is often called blue baby when occurring in infants. Cyanosis is an indicator that the body is not getting enough oxygen-rich blood. Other signs and symptoms may include:
Edema (swelling) in the legs and abdomen
Enlargement of the liver
Breathlessness
Like other babies with congenital heart disease, infants with Ebstein’s anomaly are weak and easily fatigued. Feeding time can be especially difficult. Fainting may also occur.
In very severe cases, the child will exhibit cyanosis and a condition called metabolic acidosis (excess acid in the blood) within hours of birth. These children should be treated on an emergency basis and taken into surgery at the first available opportunity. Other children, with less severe abnormalities, may develop symptoms more slowly and exhibit symptoms of heart failure within the first few weeks of life. In more mild cases, symptoms may not be apparent until later childhood. Those who have heart failure as infants have a more serious form of the condition, and they will need to be monitored more closely after surgery.
Among less severe cases of Ebstein’s, signs and symptoms may not appear until well into adulthood. These signs and symptoms may include:
Breathlessness after exercise
Fatigue
Cyanosis
Palpitations (fast or pounding heart beat)
Diagnosis methods for Ebstein’s anomaly
Among more severe cases, a physical examination will most likely indicate that something is preventing the baby from thriving in the first few days of life. Additional tests may be ordered to assess for heart problems, including:
Chest x-ray. A noninvasive radiation-based imaging test that offers the physician a picture of the general size, shape and structure of the heart and lungs.
Electrocardiogram (EKG). A painless recording of the heart’s electrical activity as a graph on a moving strip of paper or video monitor. The highly sensitive electrocardiograph machine helps detect heart irregularities, disease and damage by measuring the heart’s rhythms and electrical impulses.
Echocardiogram. This noninvasive test uses sound waves to visualize the structures and functions of the heart. A moving image of the patient’s beating heart is played on a video screen, where a physician can study the heart’s thickness, size and function. The image also shows the motion pattern and structure of the four heart valves, revealing any potential leakage (regurgitation) or narrowing (stenosis). During this test, a Doppler ultrasound may be done to evaluate cardiac blood flow.
Computed tomography scan (CAT scan) and magnetic resonance angiogram (MRA). Painless tests that are very useful for identifying coronary aneurysms.
Treatment and prevention
The treatment for Ebstein’s anomaly depends on the severity of the condition. If symptoms do not appear until adulthood, the defect may be managed with medications. If the defect is caught during childhood, but is not especially severe, the physician may choose to postpone surgery until the child has grown some.
Severe Ebstein’s, however, may require open-heart surgery at the earliest possible date. The surgery to repair the defect involves several steps, including:
Replacing or repairing the tricuspid valve (repair is the preferred method)
Closing the atrial septal defect (if one is present)
Stitching up or removing the damaged muscle portion of the ventricle (if weakened from overexertion)
Reducing the size of the atrium (if enlarged)
Because this condition is so rare, treatment success depends in part on the skill of the medical personnel who are involved in the surgery. It is important to consult with pediatric cardiologists, surgeons and hospitals that specialize in the diagnosis, repair and medical management of these types of congenital defects. The patient’s outcome after surgery is also dependent on:
Age at the time of surgery (generally the younger, the better).
The extent to which the tricuspid valve is displaced, and the amount of blood that has been leaking back in the wrong direction.
The extent to which the heart muscle sustained damage from overexertion.
The patient’s symptoms.
The degree of enlargement of the right atrium can affect the overall ability of the heart to function over the long term. Also, the earlier symptoms present themselves, the more severe the condition and the higher the chance of developing early heart failure.
If leakage from the tricuspid valve is mild and tests reveal no abnormal heart rhythms (arrhythmias), most patients can benefit from exercise, according to the American Heart Association. Patients are advised to first consult their cardiologist, who may rule out certain high-intensity activities.
Like some other congenital heart defects, the cause of Ebstein’s anomaly is unknown. However, pregnant women who have been taking lithium (a treatment for bipolar disorder) are encouraged to speak with their physician or psychiatrist about the benefits and risks of this medication. Some data have suggested that taking lithium during pregnancy can increase the risk of birth defects, including Ebstein’s anomaly.
Questions for your doctor
Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients (or parents) may wish to ask their doctor the questions about Ebstein’s anomaly:
How severe is my (or my child's) Ebstein’s anomaly?
What diagnostic tests may be performed to confirm the diagnosis?
Are there any other congenital heart defects present?
What treatment options are appropriate for me (or my child)?
Must my (or my child's) Ebstein’s anomaly be treated immediately or can treatment be delayed? If so, for how long?
How does Ebstein’s anomaly treated in childhood affect me (or will affect my child) as an adult?
What precautions and monitoring are needed, and are they necessary for the rest of a person’s life?
Should I (or my child) avoid any types of exercise or sports?
Does the condition run in families? Should other members of my family be evaluated for this condition?
Are all children with Ebstein's anomaly normally expected to have surgery?
If my first child is born with Ebstein's anomaly, will all of my other children have it as well?
The signs and symptoms of Ebstein’s anomaly depend on the severity of the condition. Among more severe cases, the skin may be slightly blue (cyanosis), a condition that is often called blue baby when occurring in infants. Cyanosis is an indicator that the body is not getting enough oxygen-rich blood. Other signs and symptoms may include: