2. Introduction
▪ Tetralogy of Fallot (TOF) is one of the most common congenital
heart disorders (CHDs).
▪ This condition is classified as a cyanotic heart disorder, because
tetralogy of Fallot results in an inadequate flow of blood to the
lungs for oxygenation (right-to-left shunt)
▪ Patients with tetralogy of Fallot initially present with cyanosis
shortly after birth, thereby attracting early medical attention.
▪ Louis Arthur Fallot, after whom the name tetralogy of Fallot is
derived
5. Haemodynamics
▪ Acyanotic Fallot :
- Obstruction to pulmonary flow is minimal
- Pink Fallot
▪ Cyanotic Fallot :
- Pulmonary resistance is high
- Increased shunting right-to-left side aggravating the central cyanosis
6. Aetiology
▪ The embryological causes is abnormal development of bulbar septum
that separates the ascending aorta from the pulmonary artery
▪ It normally aligns and fuses with the outflow part of intraventricular
septum
▪ Prenatal factors associated with a higher incidence of tetralogy of Fallot
(TOF) include maternal rubella (or other viral illnesses) during pregnancy,
poor prenatal nutrition, maternal alcohol use, maternal age older than 40
years, maternal phenylketonuria (PKU) birth defects, and diabetes.
Children with Down syndrome also have a higher incidence of tetralogy of
Fallot, as do infants with fetal hydantoin syndrome or fetal
carbamazepine syndrome.
▪ The defect occurs in about 1 in 2000 births
7. Clinical features
▪ Most infants with tetralogy of Fallot have difficulty with feeding,
and failure to thrive (FTT) is commonly observed
▪ At birth, some infants with tetralogy of Fallot do not show signs of
cyanosis, but they may later develop episodes of bluish pale skin
during crying or feeding and may become apnoeic and
unconscious – Fallot’s spells
▪ In older children, Fallot’s spells are uncommon but cyanosis
becomes increasingly apparent, stunting of growth, digital
clubbing ,polycythemia, chest pain ,headache and tachyponea
▪ Some children characteristically obtain relief by squatting after
exertion, which increases the afterload of left heart and reduces
the right-to-left shunt - Fallot’s sign
8. ▪ On examination :
▪ Combination of cyanosis with a loud ejection systolic murmur in
the pulmonary area
▪ However, cyanosis may be absent in the newborn or in patients
with only mild right ventricular flow obstruction
9. Differential diagnosis
▪ TGA with pulmonary stenosis
▪ VSD with pulmonary stenosis
▪ TGA with VSD with pulmonary stenosis
▪ VSD with pulmonary atresia
▪ Tricuspid atresia
▪ Eisenmenger’s syndrome
17. ▪ Total correction
• Brock’s procedure : The infundibulum is resected and patch
closure of VSD is done.
• Rastelli’s operation : In cases with severe hypoplasia or atresia of
right ventricular outflow
usually done after 5 yrs . Pulmonary artery is divided from
left ventricle and cardiac end is overseen. An intracardiac tunnel is
placed between large VSD and aorta.
The right ventricle is connected to divided pulmonary artery
by an aortic homograft.
19. ▪ The prognosis after total correction is good, especially if the operation
performed in childhood
▪ Follow up is needed to identify residual shunting, recurrent pulmonary
stenosis and arrhythmias
▪ An implantable defibrillator is sometimes recommended in adulthood
