Tetralogy of fallot

for UG 's

1. TETRALOGY OF FALLOT

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

3. Components P ulmonary stenosis O verriding Aorta V entricular septal defect R ight ventricular hypertrophy

4. 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

5. 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

6. 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 – F allot’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

7. 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

8. 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

9. Investigations ECG shows right ventricular hypertrophy

10. X-ray shows an abnormally small pulmonary artery and a ‘boot-shaped’ heart

11. ECHO is diagnostic and demonstrates that aorta is not continuous with ventricular septum

12. Colour Doppler Study Right and left ventriculography Aortography Cardiac catheterization

13. Management Medical line : Treatment of cyanotic spells Treatment of polycythemia Prevention of complications

14. Surgical line Palliative shunt operations - recurrent spells, children who cannot tolerate total correction, anatomical abnormality, infants with early symptoms Types : Blalock– Taussig shunt subclavian artery & pulmonary artery anastomosis Modified Blalock – Taussig shunt Gore-Tex interposition Waterson shunt Ascending aorta to right pulmonary artery Potts-Smith shunt Descending aorta to left pulmonary artery Glenn’s shunt Superior vena cava to right pulmonary artery

15. Right pulmonary artery Left pulmonary artery

16. 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.

17. Rastelli procedure

18. 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

19. Thank you A PPT BY : Vinaykumar.S.Appannavar