Cause of Cyanotic Congenital Heart Disease.
Tricuspid valve leaflets are displaced inferiorly into the RV cavity.
Results in "atrialisation" of part of the right ventricle + tricuspid regurgitation (TR).

🧬 Aetiology

Dysplastic tricuspid valve displaced inferiorly into RV.
Right atrium massively dilated, RV small and dysfunctional.
Severe tricuspid regurgitation often present.

🤝 Associations

Accessory pathway (WPW) in ~20% ⚡.
Linked with lithium exposure in pregnancy.
More common in Caucasians.

🩺 Clinical

Widely split first heart sound 🔊.
Arrhythmias & palpitations (SVT, WPW-related).
Signs of right heart failure: ascites, oedema, hepatomegaly.
Paradoxical emboli possible via associated ASD/PFO 🫀.
Severe forms → neonatal cyanosis; milder → adult diagnosis.
No sex predilection.

🧪 Investigations

CXR: Marked cardiomegaly due to huge RA.
ECG: Pre-excitation (WPW) or RBBB pattern.
Echo: Diagnostic – enlarged RA, small RV, downward displaced tricuspid valve.
Associated atrial septal defect (ASD) may be seen.

💊 Management

Medical: Diuretics, Digoxin, anti-arrhythmics.
Catheter: Radiofrequency ablation for accessory pathways.
Surgical: Tricuspid valve repair/replacement 🛠️ (challenging; risk of arrhythmias persists).
Antibiotic prophylaxis for certain procedures (per guidelines).

Cases - Ebstein’s Anomaly

Case 1 - Cyanotic Teenager: A 14-year-old boy presents with exertional dyspnoea and bluish lips. On exam: cyanosis, clubbing, widely split S2, and a tricuspid regurgitation murmur at the lower left sternal edge. ECG shows right atrial enlargement and right bundle branch block. Echocardiography reveals apical displacement of the tricuspid valve leaflets with atrialised right ventricle and right-to-left shunt through a patent foramen ovale. Diagnosis: Ebstein anomaly with cyanosis due to atrial shunt. Management: Supportive (oxygen, diuretics for right-sided heart failure) and surgical repair/replacement of tricuspid valve if severe.
Case 2 - Adult with Arrhythmia: A 32-year-old woman presents with recurrent palpitations and presyncope. ECG shows Wolff–Parkinson–White (WPW) syndrome. Echo demonstrates Ebstein anomaly with severe tricuspid regurgitation and right atrial dilatation. Diagnosis: Ebstein anomaly presenting with arrhythmia. Management: Radiofrequency ablation for WPW pathway; surgical tricuspid valve repair considered if symptomatic regurgitation or right heart failure progresses.

Teaching Commentary 💙

Ebstein anomaly is a rare congenital heart defect where the tricuspid valve is displaced apically, causing “atrialisation” of the right ventricle. Presentations vary from neonatal cyanosis to adult arrhythmia and right heart failure. Common features: cyanosis, tricuspid regurgitation murmur, arrhythmias (often WPW), and right atrial enlargement. Echo is diagnostic. Management is supportive, with surgery (valve repair/replacement, closure of atrial shunt) in severe cases. Prognosis depends on severity of valve displacement and associated lesions.

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Ebstein anomaly ❤️

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