Hypoplastic left heart syndrome — formative SAQs

SAQ 1 — The day-three collapse (10 marks, 15 minutes)

A three-day-old term infant who was feeding well presents to the emergency department in shock. The brachial and femoral pulses are both weak, the skin is grey and mottled, and the blood gas shows a pH of 7.06 with a lactate of 10 mmol per litre. The heart sounds reveal a single second sound. The working diagnosis is hypoplastic left heart syndrome. [2]

a) State the immediate pharmacological management and the principle that governs its timing. (4 marks) [2]

b) Explain the pathophysiological mechanism that links the timing of the collapse to the postnatal age. (3 marks) [3]

c) Describe the bedside and auscultatory findings that distinguish this lesion from coarctation of the aorta. (3 marks) [2]

SAQ 2 — The interstage infant (10 marks, 15 minutes)

A four-month-old infant who underwent a Norwood procedure with a right-ventricle-to-pulmonary-artery conduit at one week of age is reviewed in the cardiac clinic. The parents report two days of poor feeding, increased work of breathing and a lighter colour, and the home pulse-oximeter reads 78 percent where it usually reads 85 percent. [4]

a) State the immediate interpretation of this presentation and the most appropriate response. (3 marks) [4]

b) Explain why the interstage period carries the highest mortality in the palliation pathway, and describe the components of a home-monitoring programme. (4 marks) [6]

c) Outline the three surgical stages of single-ventricle palliation and cite the trial that informs the first-stage shunt choice. (3 marks) [1]