AKT · Child health/Congenital heartlow yield

Hypoplastic left heart syndrome

Severe underdevelopment of the left heart → duct-dependent systemic circulation

Overview

Severe underdevelopment of left-sided structures (left ventricle, aortic/mitral valves, ascending aorta) so the left heart cannot support the systemic circulation — which becomes entirely DUCT-DEPENDENT. The neonate collapses with shock as the duct closes. Prostaglandin is life-saving; management is staged Norwood surgery (or transplant), with a guarded prognosis.

Recognise

Neonatal COLLAPSE/shock (grey, poor perfusion, weak pulses, acidosis) as the duct closes — duct-dependent SYSTEMIC circulation
Often detected antenatally; single S2; signs of low cardiac output
One of the duct-dependent collapse causes (with critical coarctation/AS)

Red flags

Cardiovascular collapse on duct closure → PROSTAGLANDIN immediately + intensive care
Profound metabolic acidosis/shock

Differentials & how to tell them apart

Critical coarctation / critical ASother duct-dependent systemic-circulation collapse — echo defines; all need prostaglandin

Sepsisneonatal collapse mimic — but echo/duct-dependent picture differentiates

Investigations

Antenatal/postnatal echocardiography (hypoplastic left structures); saturations; blood gas (acidosis).

Management

Emergency prostaglandin (keep duct open) → staged Norwood surgery (or transplant)

1Suspect duct-dependent systemic circulation in a collapsed neonate; start PROSTAGLANDIN immediately and provide intensive support while planning surgery.Gate: Duct-dependent SYSTEMIC circulation — prostaglandin to keep the duct open is the immediate life-saving step; counsel the family realistically (staged Norwood palliation or transplant, guarded prognosis)
2Staged single-ventricle palliation (Norwood → Glenn → Fontan) or transplant; intensive long-term follow-up.

PROSTAGLANDIN (alprostadil) — keep the duct OPEN — life-saving while deciding on surgery/transplant

Staged Norwood surgery (or transplant) — single-ventricle palliation pathway

Key points

Neonatal collapse on duct closure + hypoplastic left heart on echo = HLHS → prostaglandin (duct-dependent systemic circulation), then staged Norwood. One of the antenatally-detected, guarded-prognosis lesions.

Monitor & prognosis

Perfusion, acidosis; staged surgery.

Guarded even with surgery.

Source: RCPCH; paediatric cardiology