Tetralogy of Fallot (TOF)

Overview

• Tetralogy of Fallot (TOF) is a congenital heart defect characterized by four structural defects.
• It is one of the most common complex congenital heart defects.
• Occurs during fetal development causing parts of the heart to form incorrectly.
• According to CDC, approximately 1 in every 2,518 births in the US has this condition.
• Known as a cyanotic heart defect due to decreased pulmonary blood flow to the lungs, leading to less oxygenated blood.

Importance of Understanding Heart Anatomy

• Blood Flow in a Normal Heart:
  • Right side of the heart receives deoxygenated blood and sends it to the lungs.
  • Left side receives oxygenated blood and sends it to the body.
  • Deoxygenated blood flows from superior and inferior vena cava to the right atrium, through tricuspid valve into right ventricle, then to lungs via pulmonary artery.
  • Oxygenated blood returns to left atrium via pulmonary veins, through mitral valve into left ventricle, then to the body via aorta.

Tetralogy of Fallot - Structural Defects

• 4 Major Defects (Mnemonic: RAPS):
  1. R: Right ventricular hypertrophy
  2. A: Aortic displacement
  3. P: Pulmonary stenosis
  4. S: Septal defect (ventricular septal defect)

Blood Flow in Tetralogy of Fallot

• Defective Flow:
  • Blood mixes due to septal defect.
  • Pulmonary stenosis restricts blood flow to lungs, reducing oxygenation.
  • Right ventricle hypertrophies due to increased resistance.
  • Aortic displacement allows mixed blood to flow into the body, leading to cyanosis.

Signs and Symptoms (Mnemonic: AFFLICT)

• A: Activity-induced cyanosis (Tet spells during crying, feeding, playing)
• F: Fingernail changes (clubbing due to chronic hypoxia)
• F: Fatigue and fainting easily
• L: Lifts knee to chest or squats to reduce Tet spells
• I: Inability to grow (smaller stature due to low oxygen)
• C: Cardiac sounds (harsh systolic murmur due to pulmonary stenosis)
• T: Trouble feeding and thriving

Management and Treatment

• Surgical Interventions:
  • Temporary surgeries to improve blood flow until full repair is possible.
  • Complete Repair: Usually performed between 6-12 months.
  • Patch to correct VSD and shunts to direct blood flow.
• Medical Management:
  • Prostaglandin (Alprostadil): Keeps ductus arteriosus open to improve pulmonary blood flow in newborns.

Nursing Considerations

• Tet Spells Management:
  • Place infant in knee-to-chest position.
  • Administer oxygen and calm the infant.
  • IV fluids to manage right-to-left shunt.
• Education:
  • Explain why children may squat during play.
  • Discuss signs of Tet spells and when to seek medical attention.

Conclusion

• Surgical correction is necessary for management of TOF.
• Early detection and intervention can improve outcomes.
• Understanding the condition's pathophysiology and symptoms helps in effective care and parent education.