Ebstein anomaly and tricuspid valve disease — formative SAQs

SAQ 1 — The cyanosed neonate with a wall-to-wall heart (10 marks, 15 minutes)

A two-day-old term infant presents with deep central cyanosis that does not improve with supplemental oxygen. On examination the precordium is hyperdynamic, there is a loud scratching pansystolic murmur at the lower left sternal edge, and the liver is palpable four centimetres below the costal margin. The chest X-ray shows a massively enlarged heart with diminished pulmonary vascular markings. A diagnosis of severe Ebstein anomaly with functional pulmonary atresia is suspected. [5]

a) Explain why this infant is cyanosed, and why the cyanosis does not improve with oxygen. (3 marks) [2]

b) Outline your immediate resuscitation, naming the specific drug, its dose and its mechanism of action. State the most important side effect and how you would manage it during retrieval to a cardiac centre. (5 marks) [3]

c) Describe how the neonatal echocardiographic severity is graded, and how the grade changes the surgical plan. (2 marks) [10]

SAQ 2 — The adolescent with Ebstein, palpitations and pre-excitation (10 marks, 15 minutes)

A fifteen-year-old boy with previously mild Ebstein anomaly presents to the emergency department with recurrent episodes of rapid palpitations and one episode of pre-syncope. His ECG shows a short PR interval with a delta wave, and he is in atrioventricular re-entrant tachycardia at two hundred and twenty beats per minute. He is successfully cardioverted. An echocardiogram confirms apical tricuspid-valve displacement with moderate tricuspid regurgitation and right-ventricular dilation. [9]

a) Explain the association between Ebstein anomaly and the ECG finding, and state the clinical significance of this association. (3 marks) [9]

b) Outline the immediate and medium-term management of his arrhythmia, including the role of electrophysiology and ablation. (4 marks) [7]

c) Describe the lifelong follow-up this patient will need, including the surgical threshold and the considerations for transition to adult care. (3 marks) [6]