Congenital Heart Disease
Dr.Nawal 17-3-2015 tue
Epidemiology and Genetic Basis of Congenital Heart Disease
PREVALENCE
0.5–0.8% of live births.
The incidence is higher in
stillborns (3–4%),
spontaneous abortuses (10–25%).
premature infants
ETIOLOGY
1-The cause is unknown.
2-multifactorial and result from a combination of genetic predisposition and
environmental stimulus.
3-A small percentage of are related to chromosomal abnormalities, trisomy
21, 13, and 18 and Turner syndrome.
Other genetic factors may have a role, e.g supracristal VSD are more
common in Asian children.
The risk of recurrence increases if a 1st-degree relative (parent or sibling) is
affected.
Evaluation of the Infant or Child with Congenital Heart Disease
divided into two Gp(physical examination + pulse oximetry
Cyanotic
Acyanotic.
2-then each groups further subdivided according to chest radiograph
(pulmonary vascular markings)increased, normal, or decreased.
3-ECG can be used to determine whether right, left, or biventricular
hypertrophy exists.
The character of the heart sounds , presence and character of any murmurs
further narrow the differential diagnosis. The final diagnosis is then
confirmed by echocardiography, CT or MRI, or cardiac catheterization.
ACYANOTIC CONGENITAL HEART LESIONS
1- volume load most common , and the most common of these are left-to-
right shunt lesions.
2- increase in pressure load, most commonly secondary to ventricular
outflow obstruction (PS, AS) or narrowing of one of the great vessels
(coarctation of the aorta).
Atrial Septal Defect
ostium secondum
Isolated secundum ASDs 7% of CHD.
defect in the region of the fossa ovalis is the most common form.
structurally normal (AV) valves.
openings ≥2 cm in diameter are
common in symptomatic older children.
Females outnumber males 3 : 1
PATHOPHYSIOLOGY
The degree of LT to-RT shunting is dependent on
-the size of the defect.
-compliance of the right and left ventricles.
- vascular resistance in the pulmonary and systemic
circulations.
large defects, the ratio of pulmonary to
systemic blood flow is usually 2 : 1 - 4 : 1.
-enlargement of the RT atrium and ventricle
dilatation of the pulmonary artery .
The left atrium may be enlarged.
the left ventricle and aorta normal in size.
pulmonary arterial pressure is usually
normal& remain normal during childhood.
CLINICAL MANIFESTATIONS
-asymptomatic; rarely produces clinically evident heart failure in childhood.
FTT may be present.
in older children, exercise intolerance
Ex/a mild left precordial bulge. RT ventricular systolic lift palpable at the
LT sternal border.
A loud S1, the S2 is characteristically fixed widely split .
A systolic ejection murmur at the left middle and upper sternal border.
A short, rumbling mid-diastolic murmur at the lower left sternal border
DIAGNOSIS
CXR varying degrees of enlargement of the RT ventricle and atrium(lateral
view), depending on the size of the shunt.
The pulmonary artery is large, and pulmonary vascularity is increased, (not
in mild cases).
ECG : hypertrophied RT ventricle;
axis may be normal or RAD
echocardiogram , shunt is confirmed by pulsed and color flow Doppler
catheterized before surgical closure
TREATMENT
Surgical or transcatheter device closure is advised for
-all symptomatic patients
-asymptomatic patients with a Qp : Qs ratio of at least 2 : 1.
The timing for elective closure is usually after the 1st yr and before entry
into school.
Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal
or Endocardial Cushion Defects
consists of contiguous atrial and ventricular septal defects with markedly
abnormal AV valves, lesion is common in children with Down syndrome.
CLINICAL MANIFESTATIONS
heart failure
intercurrent pulmonary infection in infancy.
minimal cyanosis.
failure to thrive.
Cardiac enlargement.
A precordial bulge and lift,
S1 is normal or accentuated.
The S2 is widely split if the pulmonary flow is massive.
A low-pitched, mid-diastolic rumbling murmur
at the lower left sternal border.
pulmonary systolic ejection murmur .is
produced by the large pulmonary flow.
The harsh apical holosystolic murmur of
mitral insufficiency.
DIAGNOSIS
CXR , moderate -severe cardiac enlargement caused by the prominence of
both ventricles and atria.
The pulmonary artery is large.
pulmonary vascularity is increased.
ECG in patients with a complete AV septal defect is distinctive.
The echocardiogram.
Cardiac catheterization
TREATMENT
Surgical.
Because of the risk of pulmonary vascular disease developing as early as 6–
12 mo of age, surgical intervention must be performed during infancy
.
Ventricular Septal Defect
most common CHD (25 %).
may occur in any portion of the septum, mostly(membranous type).
VSDs in the midportion or apical region of
the ventricular septum are muscular in
type and may be single or multiple
(Swiss cheese septum)
PATHOPHYSIOLOGY
determinant of the size of the LT-to-RT shunt
1-size of the VSD.
2-The level of pulmonary vascular resistance in
relation to systemic vascular resistance.
a small defect <0.5 cm2), restrictive,
the size of the defect limits the magnitude of the shunt.
In large nonrestrictive VSDs (usually >1.0
cm2), RT and LT ventricular pressure is
equalized. direction of shunting and shunt
magnitude are determined by the ratio of
pulmonary to systemic vascular resistance.
After birth size of the LT-to-RT shunt initially limited.As pulmonary
vascular resistance continues to fall in the 1st few weeks after birth left-to-
right shunt develops,
and clinical symptoms become apparent.
When the ratio of p:S resistance 1 : 1, the shunt becomes bidirectional, the
signs of heart failure abate, and the patient becomes cyanotic (Eisenmenger
syndrome).
shunt is large (Qp : Qs >2 : 1),
LT atrial and ventricular volume overload occurs, RT ventricular and
pulmonary arterial hypertension.
The main pulmonary artery, LT atrium&ventricle are enlarged
CLINICAL MANIFESTATIONS
Small VSDs with trivial left-to-right shunts, most common. asymptomatic&
found during routine physical examination
a loud, harsh, or blowing holosystolic murmur is present and heard best
over the lower left sternal border, and it is frequently accompanied by a
thrill.
.
Large VSDs
dyspnea, feeding difficulties, poor growth, profuse perspiration, recurrent
pulmonary infections.
cardiac failure in early infancy.
Prominence of the left precordium ,
palpable parasternal lift, a laterally displaced apical impulse and apical
thrust, a systolic thrill.
The holosystolic murmur less harsh than that of a small VSD ,P2 loud (
pulmonary hypertension).
mid-diastolic, low-pitched rumble at the apex (increased blood flow across
the mitral valve).
DIAGNOSIS
in small VSDs
CXR, usually normal, minimal cardiomegaly , a borderline increase in
pulmonary vasculature.
ECG normal but may suggest left ventricular hypertrophy.
In large VSDs,
CXR, gross cardiomegaly with prominence of both ventricles, the left
atrium, and the pulmonary artery
Pulmonary vascular markings are increased, and frank pulmonary edema.
ECG biventricular hypertrophy;
P waves may be notched or peaked
The two-dimensional echocardiogram, color Doppler examinatio shows the
position and size of the VSD.
The hemodynamics demonstrated by cardiac catheterization
TREATMENT
The natural course of a VSD depends on the size of the defect.
(30–50% of small defects close spontaneously, most frequently during the
1st 2 yr of life.
It is less common for moderate or large VSDs to close spontaneously,
defects large enough to result in heart failure may become smaller may close
completely.
small VSDs treat
1- reassured of the relatively benign nature of the lesion.
2- encouraged to live a normal life, no
restrictions on physical activity.
3-Surgical repair is currently not recommended.
4- protection against infective endocarditis.
monitored by clinical examination+ noninvasive laboratory tests until the
VSD has closed spontaneously.
ECG pulmonary hypertension (RVH).
Echo (confirm spontaneous closure.
.
large VSD:-
medical management has two aims:
-control heart failure: Therapeutic measures control of the symptoms and
maintenance of normal growth If early treatment is successful, the shunt
may diminish in size with spontaneous improvement, especially during the
1st yr of life.
-prevent the development of pulmonary vascular disease: Pulmonary
vascular disease can be prevented when surgery is performed within the 1st
yr of life
.
Indications for surgical closure of a VSD include
1- patients at any age with large defects in
whom clinical symptoms and failure to
thrive cannot be controlled medically.
2-infants between 6 -12 mo of age with
large defects+ pulmonary hypertension,
even if the symptoms are controlled.
3-patients older than 24 mo with Qp : Qs
ratio > 2 : 1.
4-Patients with supracristal VSD.
Severe pulmonary vascular disease is a contraindication to closure of a VSD
DIAA