What is Ebstein’s anomaly? Cardiology Basics

What is Ebstein’s anomaly? Cardiology Basics

Ebstein’s anomaly is a congenital anomaly of the tricuspid valve, which may manifest soon after birth or more commonly later in life. In Ebstein’s anomaly, two of the three leaflets of tricuspid valve are displaced further into the right ventricle. Usually anterior leaflet is not displaced while the septal and posterior tricuspid leaflets are displaced. So, a part of the right ventricle becomes part of the right atrium functionally and is called atrialized right ventricle. Undisplaced anterior leaflet is elongated.

The tricuspid valve in Ebstein’s anomaly can have severe regurgitation or stenosis, both of which leads to enlargement of the right atrium. As part of the right ventricle is taken away by the right atrium, right ventricle is small in Ebstein’s anomaly. Sometimes there is an associated atrial septal defect. As the pressure in the right atrium is usually higher than that in the left atrium in Ebstein’s anomaly, blood shunts from right atrium to left atrium.

When the right atrial blood with lower oxygen saturation mixes with left atrial blood, the oxygen content of left atrial blood decreases. This blood flows into the left ventricle, and is pumped out into the aorta. Hence systemic oxygen saturation drops and can manifest as central cyanosis in Ebstein’s anomaly.

Enlarged right atrium and the atrialized right ventricle can be the focus of cardiac arrhythmias, which could be dangerous. In addition, there could be an accessory conduction pathway from the right atrium to right ventricle. The accessory pathway also predisposes to supraventricular tachycardias. This is a reentrant tachycardia utilizing the accessory pathway and the normal atrioventricular nodal pathway.

Mild varieties of Ebstein’s anomaly may not produce many symptoms and present in adult life, often detected during routine medical examination for another reason. Severe varieties can manifest in infancy with central cyanosis. Clinical examination is characterized by multiple heart sounds because of split first and second heart sounds in Ebstein’s anomaly. Loud closure sound of the large anterior tricuspid leaflet has been called sail sound.

X-ray in Ebstein’s anomaly may show right atrial enlargement and cardiomegaly. Lung fields are relatively oligemic.

This ECG in Ebstein’s anomaly shows rsrs pattern in V2. Splintered polyphasic QRS complexes as seen in lead II are characteristic of Ebstein’s anomaly. They are also called fragmented QRS. Sometimes supraventricular tachycardia may be documented in the ECG.

This echocardiogram in Ebstein’s anomaly shows the gross distal displacement of the septal tricuspid leaflet and the atrialized portion of the right ventricle.

This colour Doppler echocardiogram shows severe tricuspid regurgitation as a bluish mosaic jet from right ventricle to right atrium.

Those with recurrent supraventricular tachycardia may need electrophysiology study by using intracardiac electrodes. Once the location of the accessory pathways are found by EP study, they can be ablated by radiofrequency catheter ablation.

Some cases of Ebstein’s anomaly may need surgical management. One important surgery for Ebstein’s anomaly is known as da Silva’s Cone procedure.