Ebstein's anomaly is a rare congenital heart defect in which part of the right ventricle becomes the right atrium. The atrium is larger than in a normal heart, while the ventricle is smaller.
This results in excessive strain on the main chamber, which leads to right heart failure. With less than 1 percent of all congenital heart defects, Ebstein's anomaly is rather rare. Women and men are equally affected.
Only 0.3-0.5 % of 1,000 newborns have Ebstein's anomaly @ alkov /AdobeStock
The symptoms can vary greatly and depend on the type of displacement and the degree of valve malformation. For example, those affected with a mild degree may be largely symptom-free. They can reach an advanced age with slight physical limitations.
The main symptoms of Ebstein's anomaly are
Severe forms of Ebstein's anomaly usually become apparent in the newborn period. In most cases, there is also a hole in the septum (between the right and left atrium). Experts also call this hole an atrial septal defect. It ensures that the blood circulates between the atria.
The atrial septal defect can be recognized by a blue coloration of the lips or hands (cyanosis). There is a risk of suffering a transient ischemic attack (TIA, precursor to a stroke) or a stroke.
Due to the overloading of the heart, performance decreases as the disease progresses. This manifests itself in increasing cardiac arrhythmia or sudden cardiac death.
In cyanosis, the blood contains too little oxygen so that it shimmers bluish through the skin @ ZayNyi /AdobeStock
Normally, the heart valve prevents blood from flowing back into the atrium. As this valve is displaced and malformed in Ebstein's anomaly, it cannot close completely. The blood flows back into the atrium. In this case, doctors speak of valve insufficiency (valve leakage).
The greater the displacement and malformation, the more pronounced the valve insufficiency. As the disease progresses, the right ventricle also enlarges as it tries to compensate for the backflow of blood and pump sufficient blood into the lungs.
The enlargement of the ventricle is also accompanied by increasing ventricular weakness. This leads to an enlargement of the entire heart and consequently to cardiac insufficiency.
The causes of valve displacement and malformation have not yet been clarified. For a long time, experts believed that taking lithium and benzodiazepines during pregnancy increased the risk for the unborn child. However, more recent studies cannot confirm this.
However, an international team of researchers was able to identify a gene mutation in some of those affected. This gene is responsible for certain building proteins in the heart muscle. Experts therefore assume that there is a genetic component in the development of Ebstein's anomaly.
The treatment of Ebstein's anomaly depends on the extent of the malformation.
The aim of current therapies is to reduce the symptoms and avoid complications (enlargement of the heart, cardiac insufficiency, cardiac arrhythmia).
Doctors use medication such as antiarrhythmic drugs to stabilize heart function and prevent cardiac arrhythmia.
Drug treatment is useful for shortness of breath, physical weakness, tiredness, water retention in the legs, palpitations and a slight enlargement of the heart.
An operation may be considered if the heart's function continues to deteriorate.
Surgery is advisable in the following cases
- Decreasing physical resilience
- Increasing heart enlargement
- Increasing cyanosis
- Pronounced tricuspid valve insufficiency with increasing symptoms
- Neurological disorders such as TIA or stroke
- Cardiac arrhythmias that cannot be treated with medication
During the procedure, cardiac surgeons repair or replace the malformed and displaced valve. They also close the hole in the cardiac septum (atrial septal defect).
The operation depends largely on the condition of the tricuspid valve leaflets and the size of the right ventricle: if sufficient natural valve material is available, valve repair (valve reconstruction) is preferable to valve replacement.
If the valve can no longer be repaired, surgeons insert an artificial valve. This can be mechanical or biological.
In the case of a mechanical valve replacement, patients must take blood thinners (Marcumar) for the rest of their lives to prevent blood clots.
In 25 percent of Ebstein's anomalies, there are additional conduction pathways in the heart that lead to uncoordinated electrical impulses(cardiac arrhythmia and atrial fibrillation). Surgeons use high-frequency current or cold (Maze procedure) to prevent these as part of a valve reconstruction.
If surgery is not possible, doctors can also use catheter ablation to obliterate and destroy the conduction pathways. In some cases, the heart beats too slowly or irregularly after the procedure, in which case a pacemaker is required.
Furthermore, doctors usually carry out endocarditis prophylaxis to prevent inflammation of the inner lining of the heart (endocarditis).
Biological heart valves last around 10 to 15 years,mechanical heart valves last a lifetime @ pirke /AdobeStock
In the case of Ebstein's anomaly, it is important to detect deterioration at an early stage in order to be able to intervene surgically in good time. Regular check-ups with a specialist are therefore essential.