Pediatric Cardiology Lecture Notes

Presentation By
Siambi Philip
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Siambi, 2021

 Congenital heart defect (CHD) may be defined as an
anatomic malformation of the heart or great vessels
which occurs during intrauterine development,
irrespective of the age at presentation
 Occur is about 0.8% of live births.
 Commonly divided into noncyanotic (L  R) and
cyanotic (R  L) categories based on direction of
shunting
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 CHD are among the most common birth defects and are
the leading cause of birth defect-related death
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Fetal circulation
● Most of CHD can be well tolerated during fetal life, becoming
apparent (sometimes dramatically) only after birth. This is because
in the fetal circulation, the right and left ventricles exist in a
parallel circuit, as opposed to the series circuit of a newborn or
adult.
● Two main structures, the foramen ovale (a communication
between right and left atrium) and the ductus arteriosus (a vessel
joining pulmonary artery and aorta) are particularly important.
During fetal life, these communications allow the more oxygenated
blood coming from placenta to perfuse preferentialy the upper part
of the body (including the coronary and cerebral arteries).
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Fetal circulation
Foramen
ovale
Ductus
arteriosus
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Fetal circulation
● After birth, mechanical expansion of the lung and
increase in arterial oxygenation rapidly lead to closure
of ductus arteriosus (by muscular contraction of this
vessel) and foramen ovale (by increasing pressure in
left atrium in respect of right atrium).
● If patency of this fetal pathways persists:
it may be by itself a CHD (causing a continuous
left-to-right shunt)
it may present an additional stress to the circulation
(e.g. in infants with pulmonary hypertension)
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 Ventricular septal defect 25-30
 Atrial septal defect (secundum) 6-8
 Patent ductus arteriosus 6-8
 Coarctation of aorta 5-7
 Tetralogy of Fallot 5-7
 Pulmonary valve stenosis 5-7
 Aortic valve stenosis 4-7
 Transposition of great arteries 3-5
 Hypoplastic left ventricle 1-3
 Hypoplastic right ventricle 1-3
 Truncus arteriosus 1-2
 Total anomalous pulm venous return 1-2
 Tricuspid atresia 1-2
 Double-outlet right ventricle 1-2
 Others 5-10
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 Atrial septal defects (ASD)
 Ventricular septal defects (VSD)
 Patent ductus arteriosus (PDA)
 Obstruction to blood flow
◦ Pulmonic stenosis (PS)
◦ Aortic stenosis (AS)
◦ Aortic coarctation
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 Most commonly asymptomatic
 Essentials of diagnosis:
◦ Right ventricular heave
◦ S2 widely split and usually fixed
◦ Systolic murmur at the pulmonary area
◦ Cardiac enlargement on CXR
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 Three major types
◦ Ostium secundum
 most common
 In the middle of the septum in the region of the foramen
ovale
◦ Ostium primum
 Low position
 Form of AV septal defect
◦ Sinus venosus
 Least common
 Positioned high in the atrial septum
 Frequently associated with PAPVR
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 Treatment
◦ Closure generally recommended when ratio of
pulmonary to systemic blood flow is > 2:1
◦ Operation performed electively between ages 1 and
3 years
 Previously surgical; now often closed
interventionally
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 Single most common congenital heart
malformation, accounting for almost 30% of
all CHD
 Defects can occur in both the membranous
portion of the septum (most common) and
the muscular portion
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 Three major types
 Small, hemodynamically
insignificant
 Between 80% and 85% of all VSDs
 < 3 mm in diameter
 All close spontanously
 50% by 2 years
 90% by 6 years
 10% during school years
 Muscular close sooner than
membranous
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 Moderate VSDs
◦ 3-5 mm in diameter
◦ Least common group of children (3-5%)
◦ Without evidence of CCF or pulmonary
hypertension, may be followed until spontaneous
closure occurs
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 Large VSDs
◦ 6-10 mm in diameter
◦ Usually requires surgery, otherwise…
◦ Will develop CCF and FTT by age 3-6 months
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 Clinical findings
◦ Medium- to high-pitched,
harsh pansystolic murmur
heard best at the left
sternal border with
radiation over the entire
precordium
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 Treatment
◦ Indicated for closure of a VSD associated with CCF
and FTT or pulmonary hypertension
◦ Patients with cardiomegaly, poor growth, poor
exercise tolerance, or other clinical abnormalities
and a P/S > 2:1 typically undergo surgical repair at
3-6 mo
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 Persistence of normal fetal vessel joining
the pulmonary artery to the aorta
 Closes spontaneously in normal term
infants at 3-5 days of age
 Epi facts
◦ Accounts for about 10% of all cases of CHD
◦ Higher incidence of PDA in infants born at high
altitudes (> 10,000 feet)
◦ More common in females
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 Accounts for about 10% of all cases of
CHD
 Higher incidence of PDA in infants born at
high altitudes (over 10,000 feet)
 More common in females
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 Clinical findings and course depend on size
of the shunt and the degree of associated
pulmonary hypertension
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 Pulses are bounding and pulse pressure is
widened
 Characteristically has a rough “machinery”
murmur which peaks at S2 and becomes a
decrescendo murmur and fades before the S1
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 Treatment consists of surgical correction
when the PDA is large except in patients
with pulmonary vascular obstructive disease
 Transcatheter closure of small defects has
become standard therapy
 In preterm infants indomethacin is used
(80-90% success in infants > 1200 grams)
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In this position a
patent ductus
arteriosus can
allow a sufficient
blood flow to the
inferior part of
the body.
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 Common in males(3:1) and account 6% of CHD
 Commonest site distal to lt subclavian artery where
arteriosus joints the aorta.
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 Symptoms and Signs:
SEVERE : Shock
MODERATE : CHF,
MILD : Headaches/epistaxis/(due htn in upper
extremities), leg claudication/hypotension and
weakness
 Decreased femoral pulses are an important sign esp. in
neonates.
 Weak and delayed femoral pulses compared to
branchial and radial pulse
 Systolic murmer heard best over sternum or aortic area.
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 ECHO : left ventricular
hypertrophy
 CXR-initially normal and later
there is notching of ribs due to
hypertrophied collateral arteries
 Treatment: For an infant in shock
-PGE1 immediately.
 Surgical vs. transcatheter repair.
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 The pulmonary valve leaflets are partly fused
together, giving a restrictive exit from the
right ventricle.
 Most are asymptomatic.
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 An ejection systolic murmur best heard at
the upper left sternal edge; thrill may be
present.
 An ejection click best heard at the upper
left sternal edge.
 When severe lesion - prolonged right
ventricular impulse, with delayed pulmonary
valve closure on auscultation.
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 Chest X-ray - Normal or post-stenotic
dilatation of the pulmonary artery.
 ECG Shows evidence of right ventricular
hypertrophy
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 Although most children are asymptomatic,
progressive right ventricular hypertrophy and
reduced exercise tolerance eventually occur.
 Transcatheter balloon dilatation is the
treatment of choice in most children
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 The aortic valve leaflets are partly fused
together, giving a restrictive exit from the left
ventricle.
 Aortic stenosis may not be an isolated lesion.
It is often associated with mitral valve
stenosis and coarctation of the aorta, and
their presence should always be excluded.
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 Most present with an asymptomatic murmur.
 Those with severe stenosis may present with
reduced exercise tolerance, chest pain on
exertion or syncope
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 Small volume, slow rising pulses
 Carotid thrill (always)
 Ejection systolic murmur maximal at the
upper right sternal edge radiating to the neck
 Delayed and soft aortic second sound
 Apical ejection click.
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 Chest X-ray Normal or prominent left
ventricle with post-stenotic dilatation of the
ascending aorta.
 ECG There may be left ventricular
hypertrophy
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 Children with symptoms on exercise undergo
balloon valvotomy.
 Balloon dilatation in older children is
generally safe and uncomplicated, but in
neonates this is much more difficult and
dangerous.
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 Tetralogy of Fallot (TOF)
 Tricuspid atresia (TA)
 Total anomalous pulmonary venous return
(TAPVR)
 Truncus arteriosus
 Transposition of the great vessels
 Hypoplastic left heart syndrome (HLH)
 Pulmonary atresia (PA) / critical PS
 Double outlet right ventricle (DORV)
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 Most common cyanotic heart disease (7 to
10% of all CHD).
 The four abnormalities include:
◦ Pulmonary stenosis
◦ RVH
◦ VSD
◦ Overriding Aorta
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 Typical features
◦ Cyanosis after the neonatal period
◦ Hypoxemic spells during infancy
◦ Right-sided aortic arch in 25% of all patients
◦ Systolic ejection murmur at the upper LSB
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 Clinical findings vary depending on degree of
Right ventricular outflow tract obstruction
 Most patients are cyanotic by 4 months and it
is usually progressive
 Hypoxemic spells (“tet spells”) are one of the
hallmarks of severe tetralogy
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 Tet spells most commonly start around 4 to
6 months of age and are charcterized by
1. Sudden onset or deepening of cyanosis
2. Sudden onset of dyspnea
3. Alterations of consciousness
4. Decrease in intensity of systolic murmur
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 Clubbing of the fingers and toes may
develop in older children.
 A loud harsh ejection systolic murmur at
the left sternal edge from day 1 of life
 With increasing right ventricular outflow
tract obstruction, the murmur will shorten
and cyanosis will increase. During a
hypercyanotic spell, the murmur will be very
short or inaudible.
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 CXR- initially normal, later in older child will
show smaller heart, possibly with an uptilted
apex (boot shaped)
 ECG - Normal at birth. Right ventricular
hypertrophy when older.
 Echocardiography
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1)Bacterial endocarditis prophylaxis is necessary.
2)Hypoxemia spell usually self limiting and
followed by sleep spells are treated if
prolonged by:
• Placing the child in a knee-chest position to
increase systemic vascular resistance and to
diminish right-to-left shunting.
• Morphine sulfate is given to depress the
respiratory center
• oxygen is administered for hypoxia
• ß-adrenergic blocking agents and
adrenergic agonists (e.g.,phenylephrine)
also have been useful.
• Bicarbonate to correct acidosis
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1)Palliative surgery.
◦ A temporary increase in pulmonary blood
flow can be obtained by the creation of a
sytemic artery-pulmonary artery shunt.
The most common shunts are the Blalock-
Taussig operation (i.e.,anastomosis of the
subclavian artery to a pulmonary artery
branch) and the modified Blalock-Taussig
operation (i.e., interposition of a tubular
graft between the subclavian and
pulmonary arteries
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2) Corrective surgery (at around 6
months of age)
◦ Consists of closing the VSD and
resecting the right ventricular
outflow obstruction (pulmonary
stenosis), enlarging the area-if
necessary-with a patch.
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 Repair may be staged (modified BT shunt) or
complete
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 The aorta arises from the right ventricle and
the pulmonary artery from the left. The blue
blood is therefore returned to the body and
the pink blood is returned to the lungs
 Unless there is mixing of blood between
them this condition is incompatible with
life. Fortunately, there are a number of
naturally occurring associated anomalies,
e.g. VSD, ASD and PDA
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 Presentation is usually on day 1-2 of life
when ductal closure leads to a marked
reduction in mixing of the desaturated and
saturated blood.
 The signs include cyanosis and cardiomegaly.
 There may be no murmur.
 An echocardiogram is diagnostic.
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 TGA with intact septum carries a poor
prognosis.
 If an infant is getting progressively
hypoxemic, it is likely that the inter-
circulatory pathways (patent foramen ovale
and patent ductus arteriosus) are closing.
 Prostaglandin (0.05 to 0.1 mcg/kg/min)
intravenously may help maintain patency of
ductus arteriosus , thus improve oxygenation.
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 Balloon atrial septostomy may be necessary
to improve hypoxemia even after PGE
 Total surgical correction by arterial switch
procedure is the treatment of choice
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 Persistent of truncus arteriosus accounts for less than
1% of all CHD
 There is only one huge great vessel arising from heart
and supplies both systemic and pulmonary arterial
blood.
 There is complete lack of formation of spiral ridges
which divide the fetal truncus arteriosus with aorta
and pulmonary artery. High ventricular septal defect
always present
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 With large pulmonary blood flow are acynotic and
present like pulmonary hypertension, hyperactive
impulse felt in apex and over xiphoid process and
systolic thrill lower sternal border
 With decreased pulmonary blood flow have marked
cyanosis, ccf, growth retardation, easy fatigability,
dyspnoea on exertion, systolic murmer on left lower
sternal border, boot shaped heart, large aorta and rt
ventricular hypertrophy
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 Accounts 2 % of all CHD
 Pulmonary venous bld doesn’t drain into lt
atrium but either drains directly or indirectly
thro systemic venous connection in the rt
atrium
 Infant look quite sick and half die within 6
months and most within a year unless
surgically corrected
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 Present with cynosis, ccf, severe tachypnoea
and a systolic murmer best heard at
pulmonary area but many cases may be
absent
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 Rare conditions account 1% of CHD
 Its failure of canalization of tricuspid valve
hence no communication between rt atrium
and rt ventricle
 Divided into 2(type 1 involve tricuspid atresia
without transposition of great arteries while
type 11 there is transposition of great
arteries)
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 Babies get cyanosed at birth, poor dev, easy
fatigability esp on feeding, dyspnoea,
tachypnoea, anoxic spells, rt heart failure,
finger clubbing, murmer which is variable
heard best at lt lower sternal border, rt atrium
enlarged
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 Varying degrees of left heart hypoplasia at
multiple levels
 Babies present in cardiogenic SHOCK once
the ductus closes.
 Immediate treatment is PGE1 intravenously
as an infusion.
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 Diastolic murmurs are never innocent
 Innocent murmurs are present in at least 50 %
of normal children
◦ Still’s murmur : low pitched, vibratory, systolic
ejection, increases with the supine position.
◦ Venous hum: continuous murmur in supraclavicular
region, reduces on lying down or with pressure on
neck.
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● Most cases of CHD are thought to be
multifactorial and result from a combination
of genetic predisposition and environmental
stimulus.
● A small percentage of CHD are related to
chromosomal abnormalities, in particular,
trisomy 21 (Down syndrome, CHD in 50% of
cases) and monosomy X (Turner syndrome,
CHD in 40% of cases).
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ETIOLOGY
● Small percentage of CHD is known to be related to a single gene
defect.
● 2 to 4% of cases of CHD are associated with known antenatal
environmental factors including maternal infections (Rubella),
excessive alcohol consumption, drugs (lithium, warfarin, thalidomide,
antimetabolites, phenitoin) and maternal illness (diabetes mellitus,
phenylketonuria, systemic lupus erythematosus).
● The incidence of CHD increases to 2-6% in 1st degree relatives of
affected patients.
Nevertheless, in most cases a clear genetic or environmental
risk factor cannot be identified.
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CHD diagnosis
Laboratory findings: polycythemia (proportional to
degree and duration of hypoxia)
Echocardiogram
ECG (electrocardiogram)
Chest X-ray
Pulse oximetry
Cardiac catheterization
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