Hypoplastic Left Heart Syndrome


Hypoplastic Left Heart Syndrome, Hypoplastic Left Heart, Hyoplasia of the Aortic Tract Complex, HLHS

  • Pathophysiology
  1. Ductus dependent lesion (along with reliance on right ventricle)
  2. Characteristic Anomalies
    1. Left ventricle hypoplasia
    2. Ascending aorta hypoplasia
    3. Aortic Stenosis (or hypoplasia or atresia)
    4. Mitral Stenosis (or hypoplasia or atresia)
  • Associated Conditions
  1. Atrial Septal Defect (ASD) or Patent Foramen Ovale
  2. Patent Ductus Arteriousus
  3. Aortic Coarctation
  • Management
  • Acute decompensation following first Norwood Procedure
  1. Apply oxygen, but aim Oxygen Saturation to 75-85%
  2. Oxygen results in vasodilation of pulmonary vessels and shunts flow away from systemic circulation
    1. Excessive oxygen risks serious Hypotension, shock or death
  3. Emergent pediatric cardiology or cardiothoracic surgery Consultation
    1. Risk of lethal shunt closure requiring immediate management
  • Management
  • Surgery
  1. Uniformly fatal without surgical correction
  2. Procedures
    1. Heart Transplantation or
    2. Norwood Procedure (3 stage, very complex repair)
      1. Establishes permanent flow between right ventricle and aorta
      2. High mortality in the first 24-48 hours of procedure
      3. Stage 1: Norwood (aorto-pulmonary artery shunt, most unstable after this stage)
      4. Stage 2: Fontan or Glenn
      5. Stage 3: Fontan
  3. Post-operative decompensation management (post-Norwood)
    1. At risk for severe decompensation even with mild Viral Infections
    2. Present with increased Systemic Vascular Resistance (cold, cyanotic digits) and Metabolic Acidosis
    3. Treatment options
      1. Avoid excessive Supplemental Oxygen (Oxygen Saturation goal 75-85%) to maintain systemic perfusion
      2. Consider small fluid Normal Saline bolus trials (5-10 ml/kg)
  • References
  1. Civitarese and Crane (2016) Crit Dec Emerg Med 30(1): 14-23
  2. Sloas and Orman in Majoewsky (2013) EM:Rap 13(9): 10-11
  3. Rao in Berger (2013) Pediatric Hypoplastic Left Heart Syndrome, Emedicine