Tetralogy of Fallot is the most common cyanotic heart defect in children, comprising four key anatomical issues: ventricular septal defect, aortic override, pulmonary stenosis, and right ventricular hypertrophy. It generally leads to significant hypoxemia due to right-to-left shunting and is associated with various chromosomal anomalies. Management often involves surgical interventions, especially for symptomatic patients experiencing cyanotic spells.

1. Tetralogy of Fallot

2.  Most common cyanotic heart defect seen in
children beyond infancy, accounting for a third
of all congenital heart disease (CHD) in this age
group

3.  Tetralogy of Fallot (TOF) is a congenital heart
defect, which has four anatomical components:
 Anterior malalignment ventricular septal defect
(VSD)
 Aortic override over the muscular septum
 Variable degrees of subvalvar, valvar, and
supravalvar pulmonary stenosis
 Right ventricular (RV) infundibular narrowing and
RV hypertrophy

5.  The four salient anatomic components of Fallot’s
tetralogy result from a specific morphogenetic
abnormality:
Malalignment of the
infundibular septum

7. Embryology
 In the normal heart, division of the fetal conotruncus
culminates in alignment of the infundibular septum
with the muscular trabecular septum
 In Fallot’s tetralogy, the infundibular septum
deviates anteriorly and cephalad and is therefore not
aligned with the trabecular septum, creating a
ventricular septal defect at the site of malalignment
 The deviation of the infundibular septum encroaches
on the right ventricular outflow tract and causes
infundibular stenosis and a biventricular (overriding)
aorta

9.  Malaligned ventricular septal defects are located
in the perimembranous septum with extension
into the infundibular septum
 Atrioventricular conduction is normal

10. Ventricular septal defect
 This condition is usually a large non-restrictive
defect (i.e. no obstruction to flow across the
VSD)
 It is often located in the perimembranous and
muscular regions of the ventricular septum,
allowing shunting of blood between the ventricles
(right to left in a classical cyanotic ToF)

11. RV outflow tract obstruction
 The obstruction to pulmonary blood flow at the
level of the RV outflow tract (RVOT) is a key
feature of ToF
 The RVOTO subsequently causes the RVH
(another key feature of ToF)
 In the presence of an unrestrictive VSD,
worsening RVOTO increases the RV pressure,
drives a right-to-left shunt through the VSD,
reduces pulmonary blood flow, and leads to
hypoxaemia

12.  Assuming the patent ductus arteriosus (PDA) is
closed and there is no collateral supply, then the more
severe the RVOTO, the more hypoxaemic the patient
may be on presentation
 A key feature is obstruction at the sub-valvular
RVOT (in 50% of patients)
 However, the obstruction may be at the pulmonary
valve (10%), above the pulmonary valve (10%), or a
mixture (30%)
 Complete occlusion of the RVOT is known as
Pulmonary Atresia

13. Overriding aorta
 This condition describes the ventriculoarterial
connection where the aorta can override the VSD to
varying degrees, because of malalignment of the
outlet component of the septum
 In ToF, the aorta still arises from the left ventricle, with
only some origin from the right ventricle
 If the aorta arises predominantly from the right
ventricle, then this abnormality may be called double-
outlet right ventricle (DORV), and the physiology is
determined by the VSD position and associated RV or
left ventricular (LV ) outflow obstruction

15. RV hypertrophy
 RV hypertrophy develops as a consequence of
the RVOTO because increased RV pressure
needs to be generated to maintain pulmonary
blood flow

16. Genetics
 Chromosomal anomalies are involved in about 12
percent of the cases, e.g. trisomy 21 (Down
syndrome), trisomy 13 (Patau syndrome) and trisomy
18 (Edwards syndrome)
 DiGeorge Syndrome 22q11 microdeletion
 Alagille syndrome
 CHARGE (coloboma, heart defect, atresia choanae,
retarded growth and development, genital
abnormality, ear abnormality) syndrome
 VACTERL

17.  Patients with TOF and Down syndrome
frequently have a particularly large VSD in the
inlet septum

19.  Coronary abnormalities occur in 5 percent,
anomalous origin of left anterior descending
(LAD) artery from the right coronary artery
(RCA) being the most common

20. Natural History
 Two thirds of patients reached their first birthday
 Approximately half reached age 3 years
 Approximately a quarter completed the first
decade of life
 The attrition rate was then 6.4% per year with
 11% alive at age 20 years
 6% at age 30 years
 3% at age 40 years

23. Natural History of Pulmonary
Atresia
 If pulmonary atresia is present as well, survival
is even poorer with only 50 percent of patients
surviving to 1 year and only 8 percent of
patients surviving to 10 years
 Adequate collateral blood flow occasionally
permits survival into adolescence and adulthood

24. Hemodynamics

25.  The important features that determine the
hemodynamic consequences in patients with
ventricular septal defect and pulmonary stenosis
are the
 Size of the defect
 The severity of the stenosis, and
 Level of systemic vascular resistance

27. ‘Pink’ Fallot
 Children with this variant are acyanotic with normal or
near-normal oxygen saturations
 There is minimal or no RVOTO
 Physiologically, the lesion behaves like a large
unrestricted VSD with a left-to-right shunt
 Patients can present with heart failure or other
features of the left-to-right shunt, although this
condition can change with time as the child grows,
and features are more like the features of a classical
ToF

28. Fallot-type pulmonary atresia (15%
of ToF)
 This type is the severest variant, characterised by
complete atresia (i.e. complete occlusion) of the
pulmonary valve
 Therefore, there is no forward flow of blood from the RV
into the pulmonary artery
 Intracardiac mixing is essential, and all pulmonary blood
flow must be supplied from the aorta either by a PDA
(‘duct-dependent pulmonary circulation’) or from major
collaterals from the aorta to the pulmonary arteries (major
aortopulmonary collateral arteries, MAPCAs)
 In the neonatal period, prostaglandin (either alprostadil
[prostaglandin E1] or dinoprostone [prostaglandin E2]) may
be required acutely to maintain any pulmonary blood flow
through the PDA

29. ToF with absent pulmonary valve
(6% of ToF)
 There is no pulmonary valve, but the RVOT is
open
 These infants are often acyanotic because there
is no RVOTO, but the condition is notable for
respiratory complications that develop secondary
to massive aneurysmal dilatation of the
pulmonary arteries caused by absence of the
pulmonary valve, with obligatory pulmonary
regurgitation
 These aneurysmal dilatations externally
compress the distal trachea and bronchi causing
intrathoracic airway obstruction, lung atelectasis,

30. Clinical Features

31.  The tetralogy usually comes to light in neonates and
infants
 When the shunt is left-to-right, initial suspicion is a
prominent systolic murmur
 When the shunt is balanced, the murmur persists in
addition to mild, intermittent, or stress-induced
cyanosis
 When the shunt is reversed, the prominence of the
systolic murmur is inversely proportional to the degree
of cyanosis

32.  The clinical course in early infancy is often benign
 Mild to moderate neonatal cyanosis tends to increase,
but cyanosis may be delayed for months and is
coupled with increased oxygen requirements of the
growing infant rather than with progressive
obstruction to right ventricular outflow
 Patients seldom remain acyanotic after the first few
years of life, and by 5 to 8 years of age, most children
are conspicuously cyanotic, with cyanosis closely
coupled to the severity of pulmonary stenosis

33.  The degree of right ventricular outflow tract
obstruction (RVOTO) often correlates with the
degree of cyanosis and the timing of presentation
 Thus patients with mild pulmonary obstruction
present late, perhaps even in adulthood, the so-
called “pink TOF”, while patients with severe
obstruction may present soon after birth on
closure of the ductus arteriosus
 In less severe cases, cyanosis is first noticed
during crying

34. Cyanotic Spells

35.  Spell usually occurs in infants between 3 to 24
months of age
 Typical spell is characterized by progressive increase
in the rate and depth of respiration, deepening
cyanosis, limpness or syncope
 Convulsions, cerebrovasclur accident and death are
potential complications
 Spells are less common after 2 years
 Initiated usually by crying, feeding or bowel
movement, spells are particularly common after
getting up from sleep

37. Wood's theory
 Hypoxemic spells are
caused by:
 Spasm of the infundibulum
of the right ventricle
 Progressively increasing
right to left shunting
 Metabolic acidosis

38. Catecholamine release
 Leads to increased myocardial contractility and
infundibular stenosis
 (both these theories do not explain the cause of
cyanotic spells in patients with tetralogy of Fallot
with pulmonary atresia).

39. Guntheroth's theory
 Episodes of paroxysmal hyperpnoea are the
cause rather than the effect of cyanotic spells
 Hyperpnoea
 Increased systemic venous return
 Right to left shunt as well as oxygen consumption
through increase work of breathing

40. Kothari's theory
 Stimulation of mechanoreceptors in the right
ventricle to be the cause of spells

41. Morgan’s theory
 Vulnerable respiratory centre which over-
reacts to hypoxic stimuli like crying, feeding

42. Young’s theory
 It was proposed that the spell was precipitated by
an atrial tachycardia

44. Squatting in TOF

45.  Squatting is of diagnostic significance in TOF
 Squatting increases peripheral vascular
resistance and thus decreases the magnitude of
the right to left shunt across the VSD
 Locking up the more desaturated lower limb
venous blood and displacing the better
oxygenated mesenteric venous blood into the
right heart may be the other benefits of squatting

47. Squatting Equivalents

49.  Recurrent hypoxic spells sometimes lead to
brain damage and mental retardation
 Cerebral venous sinus thromboses and small
occult thromboses may become manifest after
prolonged hypoxic spells

50.  Hypernasal resonance or nasal speech
(velopharyngeal insufficiency) may develop after
repeated or prolonged spells because nasal
resonance is compromised by improper
approximation of the velum (soft palate) and the
pharyngeal walls
 Brain abscess and cerebral embolism add to the
list of central nervous system complications

51.  Iron deficient erythrocytosis in patients less
than 4 years of age increases the risk of cerebral
venous sinus thrombosis
 Wheezing and stridor have been attributed to
tracheal compression by an enlarged aorta
 A stenotic pulmonary valve and an incompetent
aortic valve are substrates for infective
endocarditis

52. Physical Examination

53.  Most infants are smaller than expected for age
 Cyanosis of the lips and nail bed may be noticed at birth
or may appear later
 Cyanosis in TOF is determined by the severity of
pulmonary stenosis and also to a lesser extent by
systemic to pulmonary collaterals
 Infundibular stenosis worsens as the infant grows so that a
previously pink baby turns blue
 In the case of pulmonary atresia, cyanosis sometimes
may be absent due to systemic pulmonary collaterals
 Clubbing may be present after 3 months of life.

54.  S1 is normal, while S2 is single due to a faint P2
 Delayed and hesitant closure of the pulmonary
valve due to the slow pressure drop in the
stenotic infundibular chamber, associated valvar
stenosis and the overriding aorta all contribute to
the single S2

55.  A prominent ejection systolic murmur, is heard
at the mid and upper left sternal border
 The intensity of this murmur is inversely
proportional to the severity of stenosis
 With more severe stenosis RV pumps more into
the aorta and less across the RVOT, decreasing
the murmur
 The murmur disappears during a spell

56.  An aortic ejection click due to the dilated
ascending aorta may be heard over the apex
 A continuous murmur below the left clavicle
denotes a patent ductus arteriosus (PDA)
 A more widely heard continuous murmur,
especially over the back, is due to systemic-
pulmonary collaterals

57. Investigations

58. ECG in TOF
 In the newborn, the EKG may be normal but over
the first weeks of life normal regression of right
ventricular preponderance is not seen
 Right ventricular hypertrophy is the hallmark EKG
finding in the patient with tetralogy of Fallot and is
of value in the differential diagnosis from
ventricular septal defect
 Tall R waves in the right precordial leads (V1-V2)
are usually seen

60. Whereas the R wave in V1 is tall and usually
monophasic, R wave in V2 is much shorter –
the so called “sudden transition” is
characteristic

61.  Right-axis deviation may accompany right
ventricular hypertrophy, additionally, right atrial
enlargement is manifested by tall P waves (P
pulmonale)
 Left-axis deviation suggests an associated
complete AV canal defect
 Sudden transition of the QRS complex
morphology in leads V1 and V2 is a common
pattern in patients with tetralogy of Fallot. There is
a Rs pattern with a tall R wave in lead V1, and a
rS pattern from leads V2 or V3 to lead V6

62.  With pulmonary atresia and
an abundant collateral arterial
circulation, P waves are broad
and bifid because of increased
flow into the left atrium
 Q waves with well-developed
R waves appear in leads V5-6
because of increased flow
into the left ventricle
 ST segment and T wave
abnormalities may be found in
midprecordial leads

63. Chest Xray
 Findings on an x-ray diagnostic of tetralogy of
fallot include:
 Normal or decreased pulmonary vascularity
 Concave pulmonary artery segment
 A right sided aortic arch may also be present.
 There is pruning or reduction in the prominence of
the pulmonary vasculature over time

64. Chest X-Ray
 Plain films may classically show a "boot shaped"
heart with an upturned cardiac apex due to right
ventricular hypertrophy and concave
pulmonary arterial segment

66. -The cardiac apex
elevated
suggestive of right
ventricular
enlargement
-The main
pulmonary artery
segment is
concave
- Right-sided aortic
arch is
demonstrated
- There is
decreased
pulmonary
vascularity
(pulmonary
oligemia)

67. Echocardiography in TOF

68. Parasternal long-axis view
 Left and right ventricular size/function
 Degree of aortic override
 override of the aortic root over the
ventricular septal defect should be less
than half of the aortic diameter
 Analysis of the ventricular septal defect
 magnitude and direction of shunting
across the VSD
 Confirmation of aorto-mitral
continuity
 absence of the fibrous continuity between
the aortic and mitral valves is inconsistent
with tetralogy of fallot, and may be
suggestive of double outlet right ventricle
(DORV)

69. Parasternal short-axis view
 Location of the ventricular septal
defect
 Anatomy of the right ventricular
outflow tract
 Dilation of the RVOT may be
observed
 Dynamic obstruction of the RVOT
may be noted, resulting from
incursion of the infundibulum into
the outflow tract

70.  Pulmonic valve
 leaflet number and degree of mobility
 dimensions of the annulus
 spectral Doppler interrogation for the presence and
grading of associated pulmonic
regurgitation or stenosis

71.  Apical 4 chamber view
 Assess right and left ventricular size and function
 Right ventricular hypertrophy may be assessed by
measurement of the free wall of the right ventricle

73. Cath Study in TOF

74.  Cardiac catheterization may be necessary in few
cases to further delineate
 The levels of right ventricular outflow obstruction
 Branch pulmonary artery stenosis or hypoplasia
 Coronary artery anatomy
 Presence of aortopulmonary collaterals, and
 Presence of additional VSD

75.  The hemodynamic findings at catheterization
typically reveal normal or only mildly elevated
filling pressures
 The left and right ventricular systolic
pressures are equal
 Pulmonary artery pressures are normal or low
 The degree of right-to-left shunting is best shown
by the degree of systemic desaturation

76.  Angiographic assessment should be geared
towards the information that is needed; biplane
angiography is ideal
 RV angiogram (anteroposterior [AP] cranial, left
anterior oblique [LAO] view) shows simultaneous
opacification of aorta and PA, RVOT obstruction
and PA anatomy

78.  An aortic root injection will usually provide
adequate identification of the coronary arteries,
although selective injections may occasionally be
needed
 The arch and descending aorta may also be seen
in this view and show a PDA or collateral vessels
 If collateral vessels are identified, selective
injections are helpful to assess the areas of the
pulmonary bed that they supply and whether they
are the sole supply to these areas

79.  The VSD is best seen from a left ventricular
injection in a long axial oblique projection
 Multidetector computed tomography (MDCT)
angiography is a safe and effective non-invasive
technique to answer questions remaining after
echocardiography in patients with TOF
 Major aortopulmonary collateral arteries (MAPCA)
from all sources are best shown by this technique

80. Management

81. Management of
Cyanotic Spells

83.  A cyanotic spell is usually self limiting and lasts
less than 15-30 minutes
 But sometimes they can be prolonged and
require emergency measures like:

84. 1.
 Hold the child in knee chest position
 This increases the SVR and decreases the
desaturated systemic venous return

86. 2.
 Calm the child. The ideal sedative is morphine
 It causes respiratory centre suppression and
sedation thereby reducing hyperpnea
 Decreases systemic venous return (venodilator) and
relax the infundibulum
 The dose of morphine is 0.1 mg/kg and it can be
given intravenous (IV), intramuscular (IM) or
subcutaneous. It may be repeated after 5 minutes.
The ventilation facilities should be at hand

87.  The other alternative sedatives are:
 Midazolam 0.05–0.1 mg/kg (IV, intranasal or
intrarectal) or
 Dexmedetomidine 0.5 -1 mcg/kg IV or
 Fentanyl 1–2 mcg/kg IV
 Ketamine has dual benefit of causing sedation and
increasing SVR. The dose is 0.25- 1.0 mg/kg IV or
IM.

88. 3.
 100% Oxygen supplementation
 This causes pulmonary vasodilation and hence
decreases the pulmonary vascular resistance
(PVR)

89. 4.
 Sodium bicarbonate in a dose of 1–2 meq/kg IV
is given slowly to correct metabolic acidosis
 This may reduce the respiratory centre
stimulating effect of acidosis and may diminish
the increase in pulmonary vascular resistance
caused by hypoxia and acidosis
 It can be repeated in 10-15 minutes

90. 5.
 Beta blockers like injection propanolol is given in
a dose of 0.1-0.2 mg/kg IV over 5 minutes and
can be repeated once after 15 minutes
 It decreases the heart rate, infundibular spasm
and increases SVR
 If propanolol is not available then injection
metoprolol can be given

91. 6.
 In refractory cases vasopressors can be given to
increase the SVR and promote the redirection of
blood flow through the pulmonary circulation
 Phenylephrine a alpha-adrenergic blocker can
be given in a dose of 5 to 20 mcg/kg IV bolus,
followed by an infusion of 0.1 to 0.5 mcg/kg/min

92. 7.
 Avoid any actions that agitate the baby like
vigorous examination, repeated attempts to
venipuncture etc
 The drugs to be avoided are inotropes (e.g.
digoxin, dopamine, or dobutamine) and diuretics.

93.  If the spell is persistent or refractory, then
intubation and mechanical ventilation maybe
required
 A emergency Blalock-Taussig (BT) shunt /
pulmonary balloon valvuloplasty (PBV) may be
required in refractory cases

94. Transcatheter Interventions In
TOF
 Balloon dilatation of pulmonary stenosis
 Balloon dilatation and/or ductal stenting
 Balloon dilatation of peripheral pulmonary artery
stenosis with or without stenting
 Stenting of RVOT for infundibular stenosis by balloon
expandable stainless steel stents (Johnson &
Johnson).
 Transcatheter pulmonary valve replacement

95. Pulmonary Balloon
Valvuloplasty
 Balloon dilatation of pulmonary stenosis may be
an effective palliative procedure in a subset of
patients, obviating the need for a palliative shunt
 The PBV is recommended if the patient’s size or
cardiac anatomy makes that patient an unsuitable
candidate for total surgical correction

96.  The valvar obstruction should be a significant part of
the RVOTO obstruction
 Also due to the multiple obstructions in the RVOT, the
subvalvar obstruction still remains thus preventing
flooding of the lungs after PBV
 The supravalvar pulmonic stenosis, if discrete, can be
relieved by balloon dilatation
 With the balloon dilatation, immediate surgical
intervention with high risk is avoided

98. Advantages of Pulmonary Balloon
Valvuloplasty
 Substantial increase in saturation (SO2)
 Growth of pulmonary valve annulus and
pulmonary arteries
 The need for transannular patch is reduced by
40 percent
 The high risk intracardiac repair (ICR) is
postponed in infants
 PBV in TOF acts as a safe bridge to surgery.

99. Disadvantages of Pulmonary
Balloon Valvuloplasty
 Pulmonary balloon valvuloplasty may not be
successful in all patients
 Very rarely in severely hypoxic and sick patients
with very low SO2 the very attempt to cross the
infundibulum can precipitate the cyanotic spell
 The mortality can occur due to either cyanotic
spell or tamponade in very sick infants

100. Palliative
procedures
augmenting
pulmonary blood
flow

101. Shunt operations
 Designed to reduce cyanosis
 Pott shunt
 Waterston shunt
 Blalock-Taussig shunt

102. Blalock-Taussing shunt
(classical)
 Subclavian artery to pulmonary artery
anastomosis (end-to-side)
 Infrequently, this may lead to pulmonary
hypertension

103. Blalock Taussing shunt
(Classical)
 Originally, the shunt sacrificed the subclavian
artery (with a distal ligation) and the proximal portion
is routed downwards to an end to side anastomosis
with the ipsilateral branch of the pulmonary artery

105. Blalock Taussing shunt
(Modified)
 Uses a synthetic graft, usually expanded
polytetrafluoroethylene (Gore-Tex), to connect the
arteries
 Interposition graft between subclavian artery and
ipsilateral pulmonary artery

107. Pott shunt
 It consists of a shunt formed between the
descending thoracic aorta and the left pulmonary
artery

108. Waterston shunt
 It consists of a shunt formed between
the ascending aorta and the right pulmonary
artery

109. Surgery
 The ideal age for TOF repair remains
controversial
 Most centers prefer to operate by 1 year of age
 Transannular-transpulmonary approach is usually
followed

110. Surgical Techniques for
Intracardiac Repair

112. Indices for prediction of
success of intracardiac repai

113. Nakata index
 Sum of the cross sectional areas of the left
and right pulmonary arteries at their
prebranching points as related to body surface
area
 The normal Nakata index is + 330 mm²/m²
 An index of more than 150 mm²/m² is acceptable
for complete repair without prior palliative shunt
 Tetralogy of Fallot with pulmonary stenosis should
have an index of more than 100 for surgery

114. McGoon ratio
 Ratio of the sum of the pre branching
diameters of the left and right pulmonary
arteries to the diameter of the descending
aorta just above the level of the diaphragm
 Ratio above 1.2 is associated with acceptable
postoperative right ventricular systolic pressure in
tetralogy of Fallot

115. Contraindications to Primary
Repair

118. Pulmonary
atresia with
Fallot’s tetralogy

119.  Pulmonary atresia with Fallot’s tetralogy is the
ultimate expression of severity
 The right ventricle terminates blindly against an
atretic pulmonary valve or against imperforate
muscle
 The pulmonary trunk is either a vestigial cord or a
hypoplastic funnel-shaped channel that widens as
it approaches the bifurcation

120.  The proximal pulmonary arteries are hypoplastic
and may be discontinuous
 The entire right ventricular output enters the
systemic circulation via the nonrestrictive
malaligned ventricular septal defect

122.  The lungs are perfused by systemic-to-pulmonary
arterial collaterals on which survival depends
 Exceptionally, the pulmonary circulation is
supplied primarily, if not exclusively, by a long,
narrow sigmoid-shaped ductus arteriosus

123. MAPCAs
 Systemic arterial collaterals are classified according to
their origins as:
 Bronchial
 Originate where their name indicates and anastomose to
pulmonary arteries within the lung
 Direct systemic arterial collaterals
 Originate from the descending aorta, enter the hilum, and
then assume the structure and distribution of intrapulmonary
arteries
 Indirect systemic arterial collaterals
 Originate from the internal mammary, innominate, and
subclavian arteries and anastomose to proximal pulmonary
arteries outside the lung

124.  Systemic arterial collaterals anatomose with
pulmonary arteries in three locations: (1)
intrapulmonary; (2) extrapulmonary; and (3) hilar
 All three major types of collaterals are present when
Fallot’s tetralogy occurs with pulmonary atresia,
but only bronchial collaterals are present when the
tetralogy occurs with pulmonary stenosis,
irrespective of severity
 About 10% of arterial collaterals originate from
coronary arteries

126. FALLOT’S TETRALOGY WITH
ABSENT PULMONARY VALVE

127.  Pulmonary valve tissue is lacking completely or
consists of rudimentary remnants of avascular
myxomatous connective tissue
 Rarely, absence of the pulmonary valve occurs with
absence of a pulmonary artery and with systemic to
pulmonary artery collaterals
 Obstruction to right ventricular outflow resides at the
narrow pulmonary annulus, not at the malaligned
infundibular septum
 The pulmonary trunk, especially its proximal
branches, dilates massively together with the
infundibulum

128. Management
 The life-threatening symptom is respiratory distress in the
newborn
 It occurs predominantly in the Fallot-type APV
 Airway management as a primary procedure involves intubation,
mechanical ventilation and extracorporeal membrane
oxygenation in some infants
 Urgent complete surgical repair should relieve the compression
of the tracheobronchial tree
 This is achieved by combined anterior and posterior plication of
the pulmonary arteries or by translocation of the pulmonary
artery anterior to the aorta and away from the airways,
‘maneuver de Lecompte’ procedure

129.  Repair of pulmonary insufficiency and stenosis
requires placement of a valve conduit (homograft or
heterograft) in the right ventricular outflow tract
 Repair in the Fallot-type APV includes additional
closure of the VSD with a patch
 Asymptomatic infants can undergo repair within the
first 6 to 12 months
 Repair should however not be delayed for too long in
order to avoid the harmful effect of the dilated
pulmonary arteries on the tracheobronchial tree