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# 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

Tap one to see what it is and open it in 3D.

- [Tricuspid septal leaflet](https://durgical.com/en/anatomy/septal-leaflet-of-right-atrioventricular-valve/)
- [Tricuspid posterior leaflet](https://durgical.com/en/anatomy/inferior-leaflet-of-right-atrioventricular-valve/)
- [Right ventricle](https://durgical.com/en/anatomy/right-ventricle/)
- [Tricuspid anterior leaflet](https://durgical.com/en/anatomy/superior-leaflet-of-right-atrioventricular-valve/)
- [Right atrium](https://durgical.com/en/anatomy/right-atrium/)
- [Interatrial septum](https://durgical.com/en/anatomy/interatrial-septum/)
- [Valve rings (fibrous skeleton)](https://durgical.com/en/anatomy/fibrous-rings-of-the-heart-valves/)
- [Atrioventricular (AV) node](https://durgical.com/en/anatomy/atrioventricular-node/)
- [Bundle of His](https://durgical.com/en/anatomy/atrioventricular-bundle/)
- [Pulmonary trunk](https://durgical.com/en/anatomy/pulmonary-trunk/)

## Why it happens

- [Physiology of congenital shunts](https://durgical.com/en/physiology/physiology-of-congenital-shunts/)
- [Murmurs and the hemodynamics of valve disease](https://durgical.com/en/physiology/murmurs-and-the-hemodynamics-of-valve-disease/)

## 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](https://durgical.com/en/anatomy/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

## Red flags

- Severe cyanosis or heart failure in a newborn
- Syncope or fast palpitations (pre-excited atrial fibrillation can cause sudden death)
- New neurological deficit (paradoxical embolism)
- Progressive cyanosis or 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](https://durgical.com/en/anatomy/right-atrium/) is large and compliant.

**Tests**
ECG: tall, broad P waves (giant «Himalayan» P waves), [right bundle branch](https://durgical.com/en/anatomy/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](https://durgical.com/en/anatomy/right-ventricle/), degree of regurgitation and atrial shunt. Cardiac MRI quantifies the functional right ventricle before surgery. [Chest](https://durgical.com/en/anatomy/region/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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## Related conditions

- [Tricuspid regurgitation and tricuspid valve disease](https://durgical.com/en/conditions/tricuspid-regurgitation-and-tricuspid-valve-disease/)
- [Wolff-Parkinson-White syndrome](https://durgical.com/en/conditions/wolff-parkinson-white-syndrome/)
- [Supraventricular tachycardia (AVNRT, AVRT)](https://durgical.com/en/conditions/supraventricular-tachycardia/)
- [Atrial septal defect](https://durgical.com/en/conditions/atrial-septal-defect/)
- [Atrial fibrillation](https://durgical.com/en/conditions/atrial-fibrillation/)
- [Lithium toxicity](https://durgical.com/en/conditions/lithium-toxicity/)
- [Heart failure](https://durgical.com/en/conditions/heart-failure/)
- [Truncus arteriosus, TAPVR and tricuspid atresia](https://durgical.com/en/conditions/truncus-arteriosus-tapvr-and-tricuspid-atresia/)
- [Ischaemic stroke](https://durgical.com/en/conditions/ischaemic-stroke/)
- [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/)

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

Sources: [Ebstein anomaly](https://medlineplus.gov/ency/article/007321.htm) (MedlinePlus, US National Library of Medicine, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/conditions/ebstein-anomaly/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/ebstein-anomaly/