Tetralogy of Fallot Lecture Notes

Overview

• Tetralogy of Fallot is a congenital heart defect with four structural defects.
• One of the most common complex congenital heart defects.
• Occurs during fetal development; parts of the heart do not form correctly.
• CDC: 1 in every 2,518 births in the US.
• Known as a cyanotic heart defect: decreased pulmonary blood flow, leading to reduced oxygenation of blood.
• Results in cyanosis: bluish tint to skin due to lack of oxygen.

Normal Blood Flow Through the Heart

• Heart divided into right and left sides.
• Right side goal: Take deoxygenated blood from body to lungs for oxygenation.
• Left side goal: Send oxygenated blood from lungs to organs and tissues.
• Blood flow sequence:
  • Superior/Inferior vena cava → Right atrium → Tricuspid valve → Right ventricle
  • Pulmonic valve → Pulmonary artery → Lungs
  • Pulmonary vein → Left atrium → Bicuspid (Mitral) valve → Left ventricle
  • Aortic valve → Aorta → Body

Tetralogy of Fallot Defects

• Abnormal heart structure alters blood flow.
• Four key defects (mnemonic: RAPS):
  • R: Right Ventricular Hypertrophy
  • A: Aorta Displacement
  • P: Pulmonary Stenosis
  • S: Septal Defect (Ventricular Septal Defect)

Impact of Defects

1. Ventricular Septal Defect: Hole between right and left ventricles; blood mixes.
2. Pulmonary Stenosis: Narrowed pulmonic valve and artery, reducing blood flow to lungs.
3. Aorta Displacement: Aorta moves over septal defect, causing mixed oxygenated/deoxygenated blood flow to body.
4. Right Ventricular Hypertrophy: Right ventricle enlarges due to increased workload.

Signs and Symptoms (mnemonic: AFFLICT)

• A: Activity Intolerance
  • Stress from normal activities (crying, feeding) can lead to "Tet spells" (acute cyanosis, SOB).
• F: Fingernail Changes
  • Clubbing due to chronic hypoxia, noticeable around 6 months.
• F: Fatigue/Fainting
  • Frequent fainting during Tet spells; activity intolerance.
• L: Lift Knees to Chest/Squatting
  • Natural response to improve blood flow and oxygenation during Tet spells.
• I: Inability to Grow
  • Smaller size due to lack of oxygen for tissue and bone growth.
• C: Cardiac Sounds
  • Harsh systolic murmur and possible systolic thrill (heard at left sternal border, 2nd intercostal).
• T: Trouble Feeding and Thriving
  • Failure to thrive, low weights, delayed developmental milestones.

Treatment

• Surgery Required:
  • Temporary (palliative) or complete repair usually done between 6-12 months.
  • Procedures: Shunt placement, stent to open pulmonary artery, patch for VSD.
• Medications:
  • Prostaglandin (Alprostadil) to keep ductus arteriosus open at birth, increasing blood flow to lungs.

Key Nursing Considerations

• Monitor for Tet spells and manage with knee-chest position or squatting.
• Provide oxygen and calm the patient during episodes.
• Be aware of signs like cyanosis, clubbing, and failure to thrive.

Conclusion

• Tetralogy of Fallot is a complex yet manageable congenital defect with surgical interventions and careful monitoring.
• Ensure understanding of symptoms and emergency actions such as knee-chest position.
• Stay updated with medical guidelines and patient-specific care plans.