Tetralogy of Fallot

Question 1

What is Tetralogy of Fallot?

Answer 1

Tetralogy of Fallot is a relatively rare form of congenital cardiac disease. The clinical features of Tetralogy of Fallot are:

=> Pulmonary stenosis
=> Right ventricular hypertrophy
=> Overriding aorta
=> Ventricular septal defect.

Question 2

When does Tetralogy of Fallot present?

Answer 2

Presents around 1-2 months but may not be picked up until baby is 6 months old.

=> most common cause of cyanotic congenital heart disease

=> right to left shunt

Question 3

How does Tetralogy of Fallot present?

Answer 3

1. Tet spells (acute episodes of cyanosis)
   => during a tet spell, pulmonary stenosis causes a right-to-left shunt of deoxygenated blood across the ventricular septal defect. => this results in hypoxia, causing pain (inconsolable crying) and cyanosis.
2. Ejection systolic murmur due to pulmonary stenosis (VSD doesn’t cause a murmur)
3. Right sided aorta arch can be seen in 25% of patients
4. Chest X-ray shows boot-shaped heart
5. ECG shows right ventricular hypertrophy

Question 4

When is Tetralogy of Fallot diagnosed?

Answer 4

Commonly diagnosed antenatally or on detection of a murmur in the first few months of life.

CXR = boot shaped upturned apex

Question 5

How is Tetralogy of Fallot managed?

Answer 5

1. Definitive surgical repair to correct ventricular septal defect and widen the right ventricular outflow tract => 6-9 months

Question 6

How are Tet spells managed?

Answer 6

Managed with analgesia and supplemental oxygen.

*last line medication is a vasoconstrictive agent e.g. phenyephrine

=> vasoconstriction helps to increase systemic vascular resistance, reducing the right-to-left shunt and improving cyanosis.

Question 7

Tetralogy of fallot murmur

Answer 7

Loud, harsh murmur, upper left sternal edge - pulmonary stenosis