Congenital malformations - Edocr

194 PART V CARDIAC MALFORMATIONS
and levels of pulmonic stenosis are considered, it
is extremely common, occurring in about 25% of
all patients with congenital heart disease. Typical
pulmonary valve stenosis is usually accompanied
by a characteristic systolic murmur at the upper
left sternal border, associated with a click. If the
valve is dysplastic, the click is absent. Children
with pulmonic stenosis are usually asymptomatic
at presentation. In contrast to valvar pulmonic
stenosis, peripheral pulmonic stenosis presents
with a continuous murmur which radiates widely
to the axilla and back. Chest radiographs in pulmonic
valvar stenosis often reveal poststenotic
dilatation of the main pulmonary artery while
they are typically normal in supravalvar pulmonic
stenosis. Depending on the severity of the valvar
stenosis, ECG reveals a right axis deviation and a
variable degree of right ventricular hypertrophy.
In patients with Noonan syndrome, the axis is often
superiorly oriented. In mild peripheral pulmonic
stenosis, the ECG is usually normal.
Echocardiography with Doppler will establish the
diagnosis of pulmonic stenosis, define the level
of the lesion and estimate the pressure gradient
across the obstruction for all defects except those
in the peripheral pulmonary arteries. For those
lesions, magnetic resonance imaging (MRI) is the
preferred method of imaging. Cardiac catheterization
with balloon valvuloplasty is the preferred
treatment for patients with simple pulmonary
valve stenosis. Those with a dysplastic valve require
surgical correction.
In pulmonary atresia with an intact ventricular
septum, blood flow is maintained by a patent
ductus arteriosus. The resulting condition is entirely
different clinically from pulmonary atresia
with a ventricular septal defect (discussed in the
Chap. 28 on Conotruncal Heart Defects). There
is a spectrum of severity with some patients having
variable hypoplasia of the tricuspid valve
and of the right ventricle, which in some cases
can be severe. Myocardial abnormalities are common
with characteristic ventriculocoronary connections
referred to as sinusoids. Progressive
cyanosis is a consistent clinical finding. A systolic
murmur of tricuspid regurgitation or a continuous
murmur from the patent ductus arteriosus may be
present. On chest radiographs, there is a defect in
the area typically occupied by the main pulmonary
artery and there is decreased pulmonary
vascularity. ECG shows decreased or absent right
ventricular forces, left ventricular dominance, and
right atrial enlargement. Echocardiography with
Doppler can define the defect. Angiocardiography
is used to identify the ventriculocoronary
artery connections.
ASSOCIATED SYNDROMES
Tricuspid atresia is usually an isolated malformation
and is rarely familial. It is not a common
feature of any malformation syndrome. Some
years ago, there were reports of Ebstein anomaly
in infants exposed to lithium in utero and it
was long felt that there was a direct teratogenic
relationship between lithium exposure and this
specific congenital heart defect. Since then, additional
data have accumulated and suggest that
there is only a modest increased risk of congenital
cardiovascular defects associated with
intrauterine exposure to lithium and that the
risk is not specific for Ebstein anomaly. 1 Ebstein
anomaly can be familial, inherited in an autosomal
dominant pattern, in which case, the expression
of the defect can be highly variable
among affected family members. It can also be
associated with a newly described but relatively
common submicroscopic deletion of chromosome
1 (the 1p36 deletion syndrome). 2 This abnormality
is detected by microarray analysis.
Pulmonic stenosis occurs in a large number
of malformation syndromes. The most common
of these are listed in Table 29-1. By far the most
common condition on the list, and the most
variable in its clinical manifestations, is Noonan
syndrome (Fig. 29-1). In the neonate, the findings
in this autosomal dominant disorder can
range from overt to extremely subtle. The finding
of a dysplastic stenotic pulmonary valve in
any infant should immediately lead to the search
for other clinical features suggestive of this