Transcript Congenital Heart Diseases

Congenital Heart Diseases
-Congenital heart disease is a general term used to
describe abnormalities of the heart or great vessels that
are present from birth.
-Most such disorders arise from faulty embryogenesis,
during gestational weeks 3 through 9, when major
cardiovascular structures undergo development.
Normal
Circulation
• The aortic valve shows three thin and delicate cusps.
The coronary artery orifices can be seen just
above.The endocardium is smooth, beneath which
can be seen a red-brown myocardium. The aorta
above the valve displays a smooth intima with no
atherosclerosis.
• This is the tricuspid valve. The leaflets are thin and
delicate. Just like the mitral valve, the leaflets have
thin chordae tendineae that attach the leaflet margins
to the papillary muscles of the ventricular wall below.
• This is a normal coronary artery. The
lumen is large, without any narrowing by
atheromatous plaque. The muscular
arterial wall is of normal proportion.
Incidence & Etiology of congenital
heart abnormalities:
• 0.8% of live births (high with still births)
• Common cause of heart failure in
children
• 90% unknown etiology
• Chronic alcoholism (Ventricular Septal Defect)
• Rubella (Patent Ductus Arteriosus, Atrial Septal
Defect, Pulmonary Stenosis, etc.)
Etiology
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Multifactorial, genetic and environmental
inputs, however, are suspected, including:
chromosomal defects (trisomi 13, 21,18 and
5p deletion, 45X-Turner Syndrome)
viruses,
Chemicals, drugs such as thalidomide,
radiation.
Alcohol consumption of mother during
pregnancy causes fetal cardiac abnormalities
Classification
Clinical Consequences
The varied structural anomalies in
hearts with congenital defects fall
primarily into two major categories:
• Shunts (cyanotic)
• Obstructions (acyanotic).
• A shunt is an abnormal communication
between chambers or blood vessels
(or both).
• Abnormal channels permit the flow of
blood from left to right or the reverse,
depending on pressure relationships.
• When blood from the right side of the
heart enters the left side (right-to-left
shunt), a dusky blueness of the skin
and mucous membranes (cyanosis)
results because poorly oxygenated
blood enters the systemic circulation
(cyanotic congenital heart disease;
blue baby).
Severe, long-standing cyanosis
• Clubbing of the tips of the fingers and
toes (hypertrophic osteoarthropathy)
• Polycythemia (cerebral thrombosis).
• Left-to-right shunts are not initially
associated with cyanosis, but these
can result in progressive pulmonary
hypertension and right ventricular
overload with hypertrophy.
• Late cyanosis.
Congenital Heart Diseases
• Left-to-Right shunts.
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Atrial Septal Defect (ASD)
Ventricular Septal Defect (VSD)
Patent Ductus Arteriosus (PDA)
Atrioventricular Septal Defect (AVSD)
• Right-to-Left shunts
• Tetralogy of Fallot
• Transposition of Great Arteries
• Obstructions
• Coarctation of Aorta
• Aortic Stenosis & Atresia
• Atrophy/Hypoplasia/Abnormalities of the
Valves
Left to Right Shunts
Defect
Mechanism
There is a hole within the membranous or
Ventricular muscular portions of the inter-ventricular septum
Septal
that produces a left-to-right shunt, more severe
Defect
with larger defects. The most extreme example is
"cor triloculare biatrium", with no septum at all.
Defect
A hole in the inter-atrial septum produces a
modest left-to-right shunt. Lutembacher's
syndrome merely refers to mitral stenosis plus an
atrial septal defect.
Patent
Ductus
Arteriosus
The ductus arteriosus, which normally closes soon
after birth, remains open, and a left-to-right shunt
develops.
Atrial
Septal
Disease
Incidence
Ventricular septal defect
Atrial septal defect
Patent ductus arteriosus
Pulmonic stenosis
Tetralogy of Fallot
Coarctation of the aorta
Aortic stenosis
Transposition of great arteries
Persistent truncus arteriosus
All others
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8
8
8
8
7
6
5
1
8
%
Ventricular Septal Defect (VSD)
• There is a hole
within the
membranous or
muscular portions of
the intraventricular
septum that
produces a left-toright shunt, more
severe with larger
defects
VSD is classified according to its
size.
• 2.1. Small VSD (Maladie de Roger):
• Small VSDs (< 0.5 cm in diameter) are
common. They produce a low-volume shunt
from the left to the right ventricle during
systole.
• This shunt across a high pressure gradient
produces a loud pansystolic murmur heard
best at the left sternal edge. With a small
defect, right ventricular pressure is increased
only slightly.
• Cardiac catheterization shows entry of
oxygenated blood into the right ventricle.
• 2.2. Large VSD:
• A large VSD is much more serious, with
clinical manifestations appearing in
early childhood.
• Initially, a large volume of blood is
shunted from the left to the right
ventricle during systole, producing
volume overload of both ventricles,
hypertrophy of both ventricles, and a
pansystolic murmur.
Ventricular Septal Defect (VSD)
• Increased blood flow through the pulmonary
circulation induces pulmonary hypertension
and a loud pulmonary-valve closure sound.
• Progressive thickening and narrowing of the
small pulmonary arteries leads to increase in
right ventricular pressure, reduction in shunt
volume and, finally, shunt reversal.
• This produces cyanosis (Eisenmenger's
syndrome). Shunt reversal in VSD occurs
some time after birth (tardive cyanosis) and is
associated with decrease or disappearance
of the pansystolic murmur.
• Patients with VSD are at risk for infective
endocarditis.
ASD & VSD
• Small Defects
• No significant
shunt
• Source of Infection
• Infective
endocarditis
Atrial Septal Defect (ASD)
• A hole in the interatrial septum
produces a modest
left-to-right shunt.
• Enlarged right heart,
& pulmonary
vessels.
1.1. Ostium Secundum ASD :
• The most common type of ASD is a defect in the
development of the septum secundum, which
produces mild disease that is frequently not detected
until adult life.
• In most cases of ostium secundum ASD, the defect is
large enough (> 2 cm) to cause near equalization of
left and right atrial pressure, with flow of blood from
left to right through the ASD. In the usual case,
pulmonary flow is increased to about twice that of
systemic output, and the right ventricle is dilated and
hypertrophied owing to the volume overload.
• This is usually well tolerated, and right ventricular
failure is uncommon.
• The main complication of ostium
secundum ASD is the development of
pulmonary hypertension, increased
right side pressure, and either right
heart failure or reversal of the shunt and
cyanosis. Paradoxic embolization to
the systemic circulation and infective
endocarditis may occur.
1.2. Ostium Primum ASD:
• Ostium primum defects are rare, constituting
about 5% of all cases of ASD. They occur as
large defects in the lower part of the atrial
septum and are often associated with mitral
valve lesions.
• Ostium primum defect is common in Down
syndrome.
• Ostium primum ASD produces severe
disease in early childhood, with features of
mitral incompetence superimposed on the
ASD.
Atrial Septal Defect (ASD)
Atrial Septal Defect (ASD)
Patent Ductus Arteriosus (PDA)
• The ductus arteriosus,
serves to shunt blood
from pulmonary artery to
aorta during intrauterine
life.
• Persistence of ductus,
which normally closes
soon after birth, results
in left-to-right shunt
develops.
• Leading to pulmonary
hypertension.
Patent Ductus Arteriosus - Infant
Endocardial
Cushion Defect:
Atrioventricular septal
defect
Endocardial Cushion Defect
Right to Left Shunts
Tetralogy
of Fallot
Transposition
Great
Vessels
of
Pulmonary stenosis results in right ventricular
hypertrophy and a right-to-left shunt across a
VSD, which also has an overriding aorta
The aorta arises from the right ventricle and the
pulmonary trunk from the left ventricle. A VSD,
or ASD with PDA, is needed for extrauterine
survival. There is right-to-left shunting
There is incomplete separation of the aortic and
Truncus
pulmonary outflows, along with VSD, which
Arteriosus allows mixing of oxygenated and deoxygenated
blood and right-to-left shunting
Tetralogy of Fallot
• Pulmonic stenosis (the
aorta crunching it closed)
results in right ventricular
hypertrophy and a rightto-left shunt across a high
VSD, which also has an
overriding aorta (aorta
straddles the ventricular
septum).
• Common cause of cyanotic
heart disease.
• Tetralogy of Fallot is the most common
cyanotic congenital cardiac anomaly.
• It is characterized by:
• (1) a large ventricular septal defect;
• (2) stenosis of the pulmonary outflow tract;
• (3) dextroposition of the aorta, which
overrides the right ventricle; and
• (4) hypertrophy of the right ventricle.
• The pulmonary stenosis raises right
ventricular pressure so that the shunt across
the VSD is right-to-left, with venous admixture
of systemic arterial blood causing cyanosis.
Transposition of Great Vessels
• The aorta arises
from the right
ventricle and the
pulmonic trunk from
the left ventricle
• a VSD, or ASD with
PDA, is needed for
extrauterine
survival.
• There is right-to-left
shunting.
in Transposition of Great Vessels
• The blood flow is:
• right atriumright ventricleaorta
• left atriumleft ventriclepulmonary
artery
• If the child is to survive for any length of
time after birth, an atrial or ventricular
septal defect must be present.
• This malformation is lethal.
Obstructions
Pulmonary
Stenosis/Atresia with
Intact Ventricular
Septum
Obstruction at the pulmonary valve. When
the valve is entirely atretic, the anomaly is
commonly associated with a hypoplastic
right ventricle and an ASD.
Coarctation of
Aorta
Either just proximal (infantile form) or just
distal (adult form) to the ductus arteriosus
is a narrowing of the aortic lumen, leading
to outflow obstruction
Aortic Stenosis
and Atresia
The aortic valvular orifice may be
narrowed or stenosed by acquired disease
(RHD, degenerative calcific aortic stenosis),
by anomalous development (atresia or
stenosis), or by a combination of both
(calcification of a congenitally malformed
valve).
Coarctation of Aorta
• Either just proximal
(infantile form) or
just distal (adult
form) to the ductus
is a narrowing of the
aortic lumen,
leading to outflow
obstruction.
• Common in Turner's
syndrome.
Coarctation of Aorta (Infant)
Coarctation of Aorta
Coarctation of Aorta
• Since the lower half of the body is likely
to be under-perfused (claudication,
etc.),
• Renal hypertension is usual,
• If the femoral pulses on a hypertensive
patient seem late and weak, it's
probably coarctation of the aorta.
MALPOSITIONS of the HEART
• An acardius is a birth defect in which
there is no heart. If the pregnancy goes
to term, it is always because the child
shares circulation with a twin.
• Dextrocardia means the heart's on the
right side.
• In situs inversus totalis, with everything
backwards, the heart is usually wellformed.
• If the heart is the only organ that is malpositioned, it often bears other defects.
What kind of
abnormality is
shown here?
•Quadricuspid
pulmonary
valve.