Congenital heart disease

1. Congenital heart diseases
Dr Vinu Sugathan

6. Congenital heart diseases
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CHD refers to abnormalities of the heart or great vessels that
are present at birth.
Most CHD arises from faulty embryogenesis during gestational
weeks 3 to 8, when major cardiovascular structures form and
begin to function.

8. Etiology and Pathogenesis
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Environmental exposures (e.g., congenital rubella infection,
teratogens—including some therapeutic drugs, and gestational
diabetes)
Genetic factors. – syndromic – trisomy 21 (downs) ,trisomy13,
trisomy18,turner syndrome,Di George syndrome etc
Nutritional factors can also influence risk; folate
supplementation during early pregnancy reduces CHD incidence.

9. Clinical features
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3 major categories
Left to right shunt
Right to left shunt
Obstruction

10. • A shunt is an abnormal communication between chambers or blood
vessels
(right-to-left shunt)-hypoxemia and cyanosis (a dusky blueness of the skin
and mucous membranes) result because the pulmonary circulation is
bypassed and poorly oxygenated venous blood shunts directly into the
systemic arterial supply.
can allow emboli from the peripheral veins to bypass the lungs and directly
enter the systemic circulation (paradoxical embolism).
Severe, long-standing hypoxia/cyanosis also causes increased numbers of
circulating red blood cells (polycythemia), as well as a peculiar distal
blunting and enlargement (“clubbing”) of the tips of the fingers and toes that
can include bony changes (called hypertrophic osteoarthropathy

12. Right to left shunt (T5)
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Tetralogy of Fallot (TOF),
Transposition of the great arteries (TGA),
persistent Truncus arteriosus,
Tricuspid atresia, and
Total anomalous pulmonary venous connection.

13. Left-to-right shunts
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Atrial septal defect (ASD)
Ventricular septal defect (VSD)
Patent ductus arteriosus [PDA]

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increase pulmonary blood flow
left-to-right shunts elevate both volume and pressure in the
normally low-pressure, low-resistance pulmonary circulation.
To maintain relatively normal distal pulmonary capillary and
venous pressures, the muscular pulmonary arteries undergo
medial hypertrophy and vasoconstriction – pulmonary
hypertension

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pulmonary arteries can even develop frank atherosclerotic
lesions
The right ventricle also responds to the pulmonary vascular
changes by undergoing progressive hypertrophy.
Eventually, pulmonary vascular resistance approaches systemic
levels, and the original left-to-right shunt becomes a right-to-left
shunt that introduces poorly oxygenated blood into the systemic
circulation (Eisenmenger syndrome).

16. Obstructive CHD
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Obstructive CHD occurs when there is abnormal narrowing of
chambers, valves, or blood vessels
coarctation of the aorta
aortic valvular stenosis
pulmonary valvular stenosis

17. Left to right shunts
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Atrial septal defect
Ventricular septal defect
Patent ductus arteriosus

18. ATRIAL SEPTAL DEFECT
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ASDs are abnormal, fixed openings in the atrial septum caused
by incomplete tissue formation –
thIS allows communication of blood between the left and right
atria
ASD should not be confused with patent foramen ovale

20. Developmental stages of the atrial
septum
• The septum primum is a crescent-shaped membranous
ingrowth that partially separates them LA AND RA ; the remaining
anterior opening, called the ostium primum, allows movement of
blood from the right to left atrium during early fetal development.
. • The septum secundum is a subsequent membranous ingrowth
located to the right and anterior of the septum primum.
• The septum secundum grows to cover the ostium secundum,
leaving only a small channel called the foramen ovale

21. Types
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ASDs are classified according to their location.
Secundum ASD (90% of all ASDs) result from a deficient
septum secundum formation near the center of the atrial
septum
Primum anomalies (5% of ASD) occur adjacent to the AV
valves and are often associated with AV valve abnormalities
and/or a VSD.
Sinus venosus defects (5%) are located near the entrance of
the superior vena cava and can be associated with anomalous
pulmonary venous return to the right atrium.

22. ASD
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—are the most common defects to be diagnosed in adults.
usually do not become symptomatic before 30 years of age;
ASDs result in a left-to-right shunt. The resulting pulmonary flow
volumes may be two to eight times normal. A murmur is often
present as a result of excessive flow through the pulmonary
valve and/or through the ASD.
Surgical or intravascular ASD closure is the tx

23. VENTRICULAR SEPTAL DEFECT
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VSDs are incomplete closures of the ventricular septum, allowing
free communication of blood between the left to right ventricles;
they are the most common form of CHD
MORPHOLOGY
VSDs are classified according to their location and magnitude.
membranous VSD; and 90% occur in the region of the membranous
interventricular septum the majority are 2 to 3 cm in diameter.
infundibular VSD- 10% occur below the pulmonary valve
muscular VSD -within the muscular septum. 50% of small muscular
VSDs close spontaneously

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The functional consequences of a VSD depend on
- the size of the defect
-associated right-sided malformations.
. Large defects are usually membranous or infundibular, and they
generally cause significant left-to-right shunting, leading to early
right ventricular hypertrophy and pulmonary hypertension,
ultimately resulting in shunt reversal and cyanosis.

25. TREATMENT
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Surgical or catheter-based closure of asymptomatic VSD is
generally delayed beyond infancy, in hope of spontaneous
closure.
Early correction must be performed for large defects to prevent
the development of irreversible obstructive pulmonary vascular
diSEASE

26. PATENT DUCTUS ARTERIOSUS
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The ductus arteriosus arises from the pulmonary artery and joins the
aorta just distal to the origin of the left subclavian artery.
DURING INTRAUTERINE LIFE it allows blood flow from the
pulmonary artery to the aorta, thereby bypassing the unoxygenated
lungs.
In healthy term infants, the ductus constricts and is functionally
closed within 1 to 2 days of birth; this occurs in response to
increased arterial oxygenation, decreased pulmonary vascular
resistance, and declining local levels of prostaglandin E2.
Complete structural obliteration occurs within the first few months of
extrauterine life leaving behind the ligamentum arteriosum

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Ductal closure is often delayed (or even absent) in infants with hypoxia
(due to respiratory distress or heart disease) or when other congenital
defects are present, particularly VSD
PDA produces a characteristic, continuous, harsh “machinery-like” murmur.
The clinical impact of a PDA depends on its diameter and the
cardiovascular status of the individual. PDA is usually asymptomatic at
birth, and a narrow PDA may have no effect on the child’s growth and
development. Because the shunt is initially left-to-right, there is no
cyanosis. However, with large shunts, the additional volume and pressure
overloads eventually produce obstructive changes in small pulmonary
arteries, leading to reversal of flow and its associated consequences.

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In general, isolated PDA should be closed as early in life as is
feasible; therapy includes prostaglandin synthesis inhibitors and
possibly percutaneous or surgical interventions.
Conversely, preservation of ductal patency (by administering
prostaglandin E1) may be life-saving for infants with various
congenital malformations that obstruct the pulmonary or
systemic outflow tracts. In CHD with aortic valve or pulmonary
valve atresia, for example, a PDA may provide the entire
systemic blood flow or pulmonary blood flow, respectively

30. RIGHT TO LEFT SHUNTS
• The diseases in this group cause cyanosis early in postnatal life
(cyanotic CHD )

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Tetralogy of Fallot (TOF),
Transposition of the great arteries (TGA),
persistent Truncus arteriosus,
Tricuspid atresia, and
Total anomalous pulmonary venous connection

32. TETROLOGY OF FALLOT
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The four cardinal features of TOF are
(1) VSD,
(2) obstruction of the right ventricular outflow tract
(subpulmonic stenosis),
(3) an aorta that overrides the VSD, and
(4) right ventricular hypertrophy
In 1888, the French physician Étienne-Louis
Arthur Fallot recognized that these four heart problems often
happened together

33. MORPHOLOGY OF TOF
• BOOT SHAPED HEART

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10% of unoperated individuals are alive at 20 years of age, and
3% survive for 40 years.
If the subpulmonic stenosis is mild, the abnormality resembles
an isolated VSD, and the shunt may be left-to-right, without
cyanosis (so-called pink tetralogy).
With more severe right ventricular outflow obstruction, right-
sided pressures approach or exceed left-sided pressures, and
right-to-left shunting develops, producing cyanosis (classic TOF)
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35. treatment
• Complete surgical repair is possible but becomes complicated
for individuals with pulmonary atresia and dilated bronchial
arteries.

36. TRANSPOSITION OF GREAT ARTERIES
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Types
Dextro TGA (d TGA)
Levo TGA (l TGA) or congenitally corrected TGA

37. Dextro TGA
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the aorta arises from the right ventricle, and the pulmonary
artery emanates from the left ventricle
The embryologic defect in complete TGA stems from abnormal
formation of the spiraling truncal and aortopulmonary septae.
separation of the systemic and pulmonary circulations-a
condition incompatible with postnatal life unless a shunt exists
for adequate mixing of blood

38. •
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. Patients with d-TGA and a VSD (approximately 35%) often
have a stable shunt.
RV hypertrophy LV thinnedout
Treatment –
arterial switch operation, allows many patients with d-TGA to
survive into adulthood.

39. Levo TGA
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the right atrium connects to a ventricle with the internal morphology
of a left ventricle), which in turn empties into the pulmonary arteries
the left atrium connects to a morphologic right ventricle, which
empties into the aorta .
l-TGA does not lead to cyanosis and indeed can be entirely
asymptomatic,
, l-TGA will result in hypertrophy of the morphologic right ventricle
and eventually can cause heart failure;
it is also often associated with other CHD such as VSD, ASD, and
patent foramen ovale.

40. TRICUSPID ATRESIA
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Tricuspid atresia represents complete occlusion of the tricuspid
valve orifice.
It results embryologically from unequal division of the AV canal
the mitral valve is larger than normal, and there is right ventricular
underdevelopment (hypoplasia).
The circulation can be maintained by right to-left shunting through an
interatrial communication (ASD or patent foramen ovale), in addition
to a VSD that connects the left ventricle and the pulmonary artery
arising from the hypoplastic right ventricle.
Cyanosis is present virtually from birth, and there is a high early
mortalitY

42. Total anomalous pulmonary venous
connection
a rare congenital malformation in which all four pulmonary
veins do not connect normally to the left atrium.
Instead the four pulmonary veins drain abnormally to the right
atrium by way of an abnormal (anomalous) connection

43. OBSTRUCTIVE LESIONS
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COARCTATION OF AORTA
PULMONARY STENOSIS AND ATRESIA
AORTIC STENOSIS AND ATRESIA

44. COARCTATION OF AORTA
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MOST COMMON AMONG THE THREE
M:F =2:1
Turners syndrome
two classic forms:
(1) an “infantile” form—often symptomatic in early childhood—with
tubular hypoplasia of the aortic arch proximal to a PDA
(2) an “adult” form with a discrete ridgelike infolding of the aorta just
opposite the closed ductus arteriosus (ligamentum arteriosum)
distal to the arch vessels

46. • 50% of cases it is accompanied by a bicuspid aortic valve and
may also be associated with congenital aortic stenosis, ASD,
VSD, mitral regurgitation, or berry aneurysms of the circle of
Willis

47. Infantile type
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Preductal coarctation is characterized by circumferential
narrowing of the aortic segment between the left subclavian
artery and the ductus arteriosus; the ductus typically is patent
and is the main source of (unoxygenated) blood delivered to the
distal aorta.
The pulmonary trunk is dilated to accommodate the increased
blood flow; because the right side of the heart now perfuses the
body distal to the narrowed segment (“coarct”), the right
ventricle typically is hypertrophied.

48. Adult type
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more common “adult” postductal coarctation, the aorta is
sharply constricted by a tissue ridge adjacent to the nonpatent
ligamentum arteriosum
The constricted segment is made up of smooth muscle and
elastic fibers derived from the aortic media.
Proximal to the coarctation, the aortic arch and its branch
vessels are dilated and the left ventricle is hypertrophied.

49. Signs and symptoms
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Coarctation of aorta with PDA causes symptoms early in life
the delivery of unsaturated blood through the PDA produces
cyanosis localized to the lower half of the body.
Many such infants do not survive the neonatal period without
surgical or catheter-based intervention to occlude the PDA

50. coarctation of the aorta without a PDA
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Most children are asymptomatic
. Typically there is hypertension in the upper extremities with
weak pulses and hypotension in the lower extremities,
associated with manifestations of arterial insufficiency (i.e.,
claudication and coldness).
Particularly characteristic is the development of collateral
circulation between the pre-coarctation and postcoarctation
arteries through enlarged intercostal and internal mammary
arteries, often producing radiographically visible erosions
(“notching”) of the undersurfaces of the ribs.

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Mumur and thrill also present
Treatment
Surgical excision and end to end anastomosis

53. Aortic stenosis and atresia
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Congenital narrowing and obstruction of the aortic valve can
occur at three locations: valvular, subvalvular, and supravalvular.
Congenital aortic valve stenosis is an isolated lesion in 80% of
cases.
With valvular aortic stenosis, the cusps may be
hypoplastic (small),
dysplastic (thickened, nodular),
or abnormal in number (usually with one or no commissures).

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obstruction of the left ventricular outflow tract -- hypoplasia of
the left ventricle and ascending aorta, sometimes accompanied
by dense, porcelain-like left ventricular endocardial
fibroelastosis; the ductus arteriosus must be patent to allow
blood flow to the aorta and coronary arteries.
The constellation of findings is called hypoplastic left heart
syndrome, and unless PDA patency is preserved, duct closure in
the first week of life is generally lethal.

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Subaortic stenosis is caused by a thickened ring or collar of
dense endocardial fibrous tissue below the level of the cusps.
Supravalvular aortic stenosis is a congenital aortic dysplasia
with thickening and constriction of the ascending aortic wall.
Elastin gene mutations can cause supravalvular stenosis

59. Pulmonary stenosis and atresia
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frequent malformation leading to obstruction at the level of the
pulmonary valve.
the lesion can also be isolated or part of a more complex
anomaly—either TOF or TGA.
Right ventricular hypertrophy typically develop.
When the valve is entirely atretic, there is no communication between
the right ventricle and lungs. In such cases, the anomaly is
associated with a hypoplastic right ventricle and an ASD; blood
reaches the lungs through a PDA.
Mild stenosis may be asymptomatic and compatible with long life,
whereas symptomatic cases require surgical correction