Ebstein anomaly !

A birth defect where the tricuspid valve sits too low in the right ventricle and leaks. Severity ranges from mild to life-threatening.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

Ebstein anomaly is a congenital malformation of the tricuspid valve and right ventricle. The septal and posterior leaflets are attached abnormally low, displaced towards the apex, so part of the right ventricle becomes «atrialised» (functions as atrium) and the remaining functional ventricle is small. The large anterior leaflet is often sail-like. The valve usually leaks, and most patients have an atrial septal defect or patent foramen ovale.

Who gets it

Rare: less than 1% of congenital heart disease, about 1 in 20,000 live births, with no sex predominance. Presentation ranges from severe neonatal disease to adults diagnosed incidentally or after an arrhythmia.

Causes

Failure of the tricuspid leaflets to separate (delaminate) from the right ventricular wall during development
Usually sporadic; occasional familial cases and gene variants affecting cardiac muscle
Association with maternal lithium use in early pregnancy (the absolute risk is small)

Risk factors

Maternal lithium therapy in the first trimester
Family history of congenital heart disease

Pathophysiology

Downward displacement of the leaflets and leaflet tethering cause tricuspid regurgitation into a large right atrium that includes the atrialised ventricle. The small functional right ventricle delivers little forward flow. Raised right atrial pressure pushes blood across the atrial defect, producing right-to-left shunting and cyanosis. In the newborn, high pulmonary resistance makes this worse until resistance falls. Accessory atrioventricular pathways near the malformed valve are common, causing Wolff-Parkinson-White syndrome and supraventricular tachycardias.

Classification

Carpentier classification (types A–D) by size and mobility of the anterior leaflet and the functional right ventricle
Neonatal severity scores based on the ratio of right atrium plus atrialised ventricle to the rest of the heart (for example the Celermajer index)

Symptoms and signs

Newborn: cyanosis, heart failure and respiratory distress in severe forms
Children and adults: exercise intolerance, fatigue and dyspnoea
Palpitations from supraventricular tachycardia or atrial arrhythmias
Cyanosis on exertion (right-to-left shunt)
Oedema and hepatomegaly in advanced right heart failure

Diagnosis

Clinical: Widely split S1 and S2 with extra sounds (triple or quadruple rhythm), holosystolic tricuspid regurgitation murmur at the left lower sternal border, cyanosis of variable degree; jugular pulsations may be modest despite severe regurgitation because the right atrium is large and compliant.
Tests: ECG: tall, broad P waves (giant «Himalayan» P waves), right bundle branch block, first-degree AV block or pre-excitation with delta wave. Holter or event monitoring for arrhythmias; pulse oximetry at rest and on exercise.
Imaging: Echocardiography is diagnostic: apical displacement of the septal leaflet, sail-like anterior leaflet, atrialised right ventricle, degree of regurgitation and atrial shunt. Cardiac MRI quantifies the functional right ventricle before surgery. Chest X-ray in severe cases: massive «box-shaped» cardiomegaly with reduced lung markings.

Differential diagnosis

Tricuspid regurgitation of other causes (for example endocarditis or pulmonary hypertension)
Tricuspid valve dysplasia
Pulmonary atresia with intact ventricular septum
Arrhythmogenic right ventricular cardiomyopathy
Pericardial effusion (large cardiac silhouette)

Goal of treatment

Support the newborn until pulmonary resistance falls, control arrhythmias and heart failure, and repair the tricuspid valve before right ventricular function deteriorates or cyanosis progresses.

Treatment

Acute: Severely affected newborns: oxygen, inhaled nitric oxide to lower pulmonary resistance, prostaglandin E1 when pulmonary flow is ductus-dependent, and inotropic support; selected neonates need early surgery.
Medical: Diuretics for heart failure; antiarrhythmic drugs for supraventricular tachycardias; anticoagulation when atrial arrhythmias or paradoxical embolism occur.
Procedure: Catheter ablation of accessory pathways (Wolff-Parkinson-White) or other atrial arrhythmia substrates; transcatheter closure of the atrial defect in selected patients.
Surgical: Tricuspid valve repair, typically the cone reconstruction, or valve replacement when repair is not possible, with closure of the atrial defect; a bidirectional Glenn may be added when the right ventricle is small.
Follow-up: Mild disease: periodic clinical review, ECG, Holter and echocardiography. Nursing: rhythm monitoring, oximetry, air filters on intravenous lines when an atrial right-to-left shunt is present, and pregnancy planning with a cardiologist.

Complications

Right heart failure
Supraventricular tachycardia, atrial fibrillation or flutter and sudden cardiac death
Paradoxical embolism, stroke and brain abscess
Infective endocarditis
Complete heart block or reoperation after surgery

Prognosis

Highly variable. Severe neonatal forms carry high mortality, while patients with mild displacement may live normally for decades. Surgical repair at experienced centres has good long-term results.

Prevention

Pre-conception counselling and fetal echocardiography for women who need lithium during pregnancy
Prenatal ultrasound screening

Test yourself

Think of the answer, then tap the question to see it.

Which tricuspid leaflets are displaced towards the apex in Ebstein anomaly?

The septal and posterior leaflets.

Which maternal drug in early pregnancy has been associated with Ebstein anomaly?

Lithium.

Which pre-excitation syndrome is frequently associated?

Wolff-Parkinson-White syndrome.

What is the classic chest X-ray appearance in severe disease?

Massive «box-shaped» cardiomegaly with reduced lung markings.

Why do many patients become cyanotic?

Right-to-left shunting through an atrial septal defect or patent foramen ovale.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Ebstein anomaly (MedlinePlus, US National Library of Medicine, 2026).

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Representative model, for educational purposes only.

Tricuspid septal leaflet highlighted on the Durgical 3D model