Ebstein anomaly and tricuspid valve disease — branching viva

Stage 1 — The cyanosed neonate

The examiner shows you a two-day-old cyanosed neonate with a wall-to-wall heart on chest X-ray and a loud tricuspid regurgitant murmur. The oxygen saturation is sixty percent and does not rise with supplemental oxygen. [5]

• What is your working diagnosis, and what bedside and radiographic features support it? Severe Ebstein anomaly with functional pulmonary atresia, supported by the huge heart, oligoaemic lungs, the murmur and oxygen-unresponsive cyanosis. [5]

• What drug do you start immediately, at what dose, and why does it work? Prostaglandin E1 at 0.01 to 0.05 micrograms per kilogram per minute; it keeps the ductus arteriosus open to supply pulmonary blood flow while the pulmonary vascular resistance falls. [3]

• What is the most dangerous side effect, and how do you manage it in transfer? Apnoea; the baby must travel intubated or with airway expertise. [3]

Stage 2 — The fetus with hydrops

The examiner moves to the antenatal clinic. A twenty-four-week fetus has Ebstein anomaly with ascites and skin oedema. [10]

• How is fetal and neonatal severity graded, and what does the grade predict? The Great Ormond Street Echocardiography score grades severity one to four; scores of three and four and the presence of hydrops predict high mortality. [10]

• What is the significance of hydrops, and what prenatal intervention may be considered? Hydrops carries the gravest prognosis; prenatal non-steroidal anti-inflammatory therapy may close a circular shunt and reverse hydrops in a specialist fetal centre. [3]

• Outline the surgical pathways and what drives the choice: cone reconstruction for the patient with a functional right ventricle, and the modified Starnes single-ventricle pathway for the most severe neonate. [8]

Stage 3 — The adolescent with palpitations

The examiner moves to the emergency department. A fifteen-year-old with known mild Ebstein presents with rapid palpitations and pre-syncope, and the ECG shows a delta wave and short PR interval. [9]

• What is the significance of the ECG finding, and what is the dominant late risk? About a fifth of Ebstein patients have an accessory pathway, the highest of any structural lesion; atrial arrhythmia is the leading cause of sudden death. [9]

• Outline the management of the arrhythmia, including the role of electrophysiology. Electrophysiological study with accessory-pathway ablation, before or at the time of cone-repair surgery. [7]

• Why does this patient need lifelong surveillance even if his valve is only moderately affected? Recurrent tricuspid regurgitation, right-ventricular failure and late arrhythmia all declare over decades; no Ebstein patient is discharged from cardiac follow-up. [6]