This document discusses the classification, symptoms, diagnosis, and treatment of tetralogy of Fallot (TOF), a congenital heart defect. TOF is characterized by four components: pulmonary stenosis, overriding aorta, ventricular septal defect, and right ventricular hypertrophy. Symptoms in infants include cyanosis that worsens with activity due to reduced pulmonary blood flow. Diagnosis involves examination findings like a murmur, ECG showing right ventricular hypertrophy, and CXR/ECHO images. Treatment ranges from medical management to palliative surgeries like Blalock-Taussig shunts or corrective repair via surgery to close defects.

1. Dr. Keith Mugarura
Pediatrics and Child Health
College of Health Science
Makerere University
Venue: Uganda Heart Institute, 2010

2. Classification of TOF

3. Components TOF
(POVR)
1. Pulmonary stenosis
2. Overriding Aorta
3. Ventricular septal defect
4. Right ventricular hypertrophy
• (May have Tricuspid Atresia and hence the
term Psuedo-truncus)
• Some have described a pentalogy (TOF+ASD)

5. Hemodynamic lesions of TOF

6. Shunt
Shunt vol depends on relative resistance in the
• Pulm Artery
• Systemic Circulation

7. Xteristics Symptoms

8. • Neonatal period to 1 year of age
• Degree of Cyanosis related to:
 Severity of Pulm stenosis
 Degree in reduction of Pulm blood flow
 Lowering the SVR (e.g meals, exercise, hot
weather)- incr Rt to Lt shunt.

9. • A.k.a Tetrad spells or ‘’tet’’ spells
• Common in unoperated children
• May be caused contraction of the Rt Vent
Infundibulum hence incr degree of Pulm
stenosis
• Xterized by:
 Dysnea
 Intense Cyanosis
 Death due to hypoxia

10. • Almost diagnostic for TOF
• During exertion child squats to rest
• Squatting:
 Incr Systemic Vascular Resistance hence
reduce Rt to Lt shunt
 Incr Systemic Venous Return hence
improvement of Rt Vent Stroke Vol and Pulm
blood flow

11. TOF and CCF

12. Phys Exam
• Normal cardiac size
• Harsh ejection systolic mummur (M&ULSB)-
mummur is of Pulm stenosis and not VSD
• Mummur α ___1___ (soft mummur with severe stenosis)
stenosis
• If mummur is continous- think Pulm valv
atresia (represent PDA, bronchial pulm
arteries)

13. ECG
• Right axis deviation.
• Right ventricular hypertrophy (tall R wave in
V1 and deep S wave in V6)
• Rt Vent Hypertrophy assoc with upright T
waves in V1
• Tall P waves indicate right atrial enlargement.

14. CXRAY
• The heart size is normal.
• The cardiac contour is boot-
shaped (apex is turned upward, and the PA
segment is concave because the pulmonary
).
artery is small
• Right ventricular hypertrophy
and right atrial enlargement.
• The ascending aorta is
enlarged (25% of the cases, a
right aortic arch).

15. ECHO
• Parasternal view Long Axis:
 Large Ao root overridding large VSD (Images almost
similar to Truncus and DORV)
 PA arises from RV but infundibulum,
pulmonary valve annulus, and pulmonary
arteries appear small
 PDA- in neonate is long and convoluted
• Doppler-Acc turbulent flow thru RVOT-
Laminar to distrurbed color signals at most
prox site of obstruction (infundibulum)

16. Cardiac Cath in TOF
• No sign of Lt to Rt shunt
• Desat found in Ao blood
• Pressure drop across out flow area of RV (avoid
cath in RVOT coz of infundibular spasms= ‘’tet’’ spell)
• RV angiography-
 Site of the stenosis, outline the pulm art tree,
opacification of Ao.
 Ao root injxn-anomalies of coronary art that may be
catastrophic during Sx

17. Mx of TOF
• Medical
• Operative:
 Palliative
 Corrective

18. Medical
• Mx IDA ( functional anemia: insufficient HB to counteract level of
hypoxemia).
• Tetrad spell

19. Tetrad Spell

20. Tet Spell cont

21. Operative Mx
Palliation: (Small infants, small PAs, capacity of cardiac centers)
Palliation
• Blalock–Taussig (1945)-shunt (anastomosing a subclavian
artery to a branch pulmonary artery)
• Waterston shunt (creating a communication between the
right pulmonary artery and the ascending aorta)
• Potts procedure (creating a communication between the left
pulmonary artery and the descending aorta) were developed.
• Potts and Waterston are not used anymore, because of the
tendency to create too large a communication, resulting in
pulmonary vascular disease.

22. Modified Blalock-Taussig Shunt
• Used in small infants with significant cyanosis
• Older children with TOF whose PA is are too
small for operation.
• (It consists of: synthetic tube (polytetrafluoroethylene or
GoreTex), usually 4 mm in diameter, that connects a
subclavian artery and a branch pulmonary artery)
• Goal of Palliation-Incr PBF and improve art
sats

23. Corrective Repair
• Close VSD with a VSD Patch
• RVOT Patch after resecting the Pulm stenosis
may have incomp valve post op (replace valve
in same op?)
• If norm Pulm annulus diameter-may resect
infundibular stenosis without right
ventriculotomy and have good pulmonary
valve function postoperatively.

24. Complications
• Arrythmias, Rt and Lt Vent Dysfxn
• Pulm Regurg, if no valve replmnt (classical
repair) and transmural rt vent scar
• Always have an RBBB on ECG (patch on Rt
Vent side)
• Patch Dehiscence
• Long term CNS effect on school perfomance?
• SCD

25. Caution
• Symptoms progress in patients with tetralogy of Fallot
because of Increasing infundibular stenosis.
• Increasing frequency or severity of symptoms, rising
hemoglobin, and decreasing intensity of the murmur are signs
of progression.
• Electrocardiogram and chest X-ray may show no change.

26. Thank You