Peds

Tetralogy of Fallot

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Tetralogy of Fallot

  • See also
  1. Tet Spell
  2. Congenital Heart Disease
  3. Congenital Heart Disease Causes
  • Epidemiology
  1. Incidence: 10-15% of Congenital Heart Disease
  2. Most common cause of CHD outside infancy
  • Pathophysiology
  1. See Tet Spell
  2. Cyanotic Congenital Heart Disease
    1. Secondary to Right-To-Left Shunt (related to VSD and often pumonary stenosis)
    2. May present in first days to month of life with Cyanosis and severe pulmonic stenosis
      1. Stabilized with PGE-1 infusion followed by endovascular ductus stent
      2. Similar initial management as with other cyanotic ductus dependent lesions
  3. Four components
    1. Primary features responsible for symptoms
      1. Large Ventricular Septal Defect (VSD)
      2. Right outflow tract obstruction
    2. Other features
      1. Right Ventricular Hypertrophy
      2. Aorta overides both ventricles (mixing oxygenated and deoxygenated blood)
  • Associated Conditions
  1. Right aortic arch (25%)
  2. Atrial Septal Defect (15%)
  3. Absent pulmonary valve
  4. Pulmonary atresia
  5. Pulmonary stenosis
  6. Atrioventricular septal defect
  7. Left superior vena cava to coronary sinus
  • Signs
  1. Oxygen Saturation is always low (e.g. 80%)
  2. Systolic ejection murmur at left sternal border
    1. Grade III+ intensity, harsh Systolic Murmur
    2. Murmur diminishes in intensity during "Tet Spell"
  3. Single S2 Heart Sound
  1. Right Axis Deviation
  2. Right Ventricular Hypertrophy
  • Labs
  1. Arterial Blood Gas
    1. Normal arterial pH
    2. Normal arterial pCO2
    3. Low arterial pO2
  • Imaging
  1. Chest XRay
    1. Heart size normal or small
    2. Narrow mediastinum
    3. Heart may appear "boot shaped" in classic presentation
  2. Echocardiogram
    1. Large Ventricular Septal Defect (VSD)
    2. Right outflow tract obstruction
    3. Right Ventricular Hypertrophy
    4. Overriding aorta
  • Management
  • Surgery
  1. Stabilized with PGE-1 infusion followed by endovascular ductus stent in first days of life before ductus closure
    1. Similar initial management as with other cyanotic ductus dependent lesions
  2. Subclavian to pulmonary artery shunt (Blalock-Taussig)
    1. Palliative or temporizing method
  3. Definitive, total repair
    1. Repair as newborn or at age 3 years
    2. Ventricular Septal Defect patch
    3. Right ventricular outflow tract widening
  • Causes
  • Cyanotic Episodes
  1. Tet Spells
  2. Hypoxia responsive to Supplemental Oxygen
    1. Impaired alveolar gas exchange (e.g. Pneumonia, Pulmonary Edema)
  3. Hypoxia UNresponsive to Supplemental Oxygen
    1. Decreased pulmonary Blood Flow via ductus arteriosus (ductus stent Occlusion, closure of unstented ductus)
  • Complications
  • Without repair (inoperable cases)
  1. Affects related to:
    1. Hypoxia
    2. Polycythemia
  2. Symptoms
    1. Headache
    2. Altered Level of Consciousness
    3. Cerebrovascular Accident
    4. Epistaxis
    5. Hemoptysis
    6. Hyperuricemia and Gout
  • Complications
  • Post-surgical correction
  1. Arrhythmia
  2. Right ventricular insufficiency
    1. Right Ventricular Failure
    2. Pulmonary insufficiency
  3. Left ventricular insufficiency
    1. Left Ventricular Failure
    2. Aortic Insufficiency
  • Prognosis
  1. Survival post-surgical repair: >95%
  2. Cognitive development may be impaired
  • References
  1. Broder (2023) Crit Dec Emerg Med 37(9): 22-3
  2. Civitarese and Crane (2016) Crit Dec Emerg Med 30(1): 14-23
  3. Cyran (1998) PREP review lecture, October, Phoenix
  4. Merenstein (1994) Pediatrics, Lange
  5. Tsze and Spangler in Herbert (2015) EM:Rap 15(4): 2-3
  6. Saenz (1999) Am Fam Physician 59(7):1857-66 [PubMed]