Tetralogy of Fallot



  • Tetralogy of Fallot is a ventricular septal defect associated with right ventricular (RV) outflow obstruction (infundibular and/or valvular pulmonic stenosis), concentric RV hypertrophy, and overriding aorta (1).
    • Pathophysiology depends primarily on severity of RV outflow tract obstruction.
    • RV and left ventricular (LV) pressures generally are equal owing to the defect.
    • RV pressures can be elevated with ventricular septal defect proximal to the level of RV obstruction.
    • Right-to-left shunting predominates, resulting in varying degrees of arterial oxygen desaturation.
  • System(s) affected: cardiovascular, pulmonary

Pediatric Considerations
Congenital disorder

Pregnancy Considerations
Pregnancy is usually well tolerated following successful surgical repair.



  • 5–10% of all congenital heart disease (1)
  • Most common cardiac anomaly within the 1st year of life requiring intervention
  • Predominant age: newborn; case reports of adult presentation
  • Predominant sex: male = female

In the United States: 3.9/10,000 live births

Etiology and Pathophysiology



  • Minority of cases are familial, autosomal dominant mode of inheritance.
  • 20% association with velocardiofacial syndrome (22q11 deletion) by FISH analysis

Risk Factors

  • Predominately sporadic
  • Increased incidence with advanced maternal age

Commonly Associated Conditions

  • Stenotic pulmonary artery
  • Patent ductus arteriosus
  • Atrial septal defect
  • Right-sided aortic arch: 25%
  • Atrial septal defect: 15%
  • Anomalous coronary arteries: 9%
  • 20–25% associated with a syndrome, including Down, Alagille, DiGeorge, and velocardiofacial

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