Tetralogy of Fallot

Description

• 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.

Epidemiology

Incidence

• 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

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

Etiology and Pathophysiology

Unknown

Genetics

• 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