Diagnostic ultrasound ( PDFDrive )

1294 PART IV Obstetric and Fetal Sonography
ability to divide, rhabdomyomas can be expected to shrink or
completely resolve, and patients can oten be treated conservatively.
204 However, because of the association of rhabdomyomas
with tuberous sclerosis and arrhythmias, prognosis remains
guarded. 205
Teratomas may appear as cystic, complex, or solid masses.
hese are intrapericardial in origin, with attachment to the aortic
root or pulmonary artery, and are virtually always associated
with a large pericardial efusion. Although teratomas are generally
considered to be benign, they can recur ater surgical excision
and may undergo malignant degeneration. 204 Fetal teratomas are
weakly associated with tuberous sclerosis. 196
Rare cardiac tumors include ibromas and hemangiomas.
Fibromas are almost always single and typically have central
necrosis and calciication. 201 Fibromas are usually located in the
ventricular septum, making resection problematic. Hemangiomas
are even rarer and are usually associated with the right atrium
or interventricular septum, oten with an intracavitary component.
Cardiac hemangiomas are heterogeneous with cystic and solid
components, oten with calciications. hey are frequently associated
with a pericardial efusion. 201
Echogenic foci within a ventricle should not be mistaken for
a cardiac tumor. hese are thought to represent areas of mineralization
of papillary muscle or chordae tendineae. hese usually
occur in the let ventricle (93%) but may occur in the right
ventricle (5%) or both ventricles (2%) and are generally clinically
insigniicant 206-208 (Fig. 37.40). Echogenic foci have been associated
with chromosomal anomalies such as trisomy 21 and 13. However,
more recent literature suggests that in isolation, in an otherwise
low-risk pregnancy, an increased risk of aneuploidy does not
exist. 208
Congenital ventricular aneurysms or diverticula may be
appreciated in utero. Both are usually isolated indings. Ventricular
aneurysms appear sonographically as an outpouching of the
ventricular myocardium that usually does not contract with the
ventricle. A diverticulum of the ventricle appears as a cystic
RV
RA
LV
LA
FIG. 37.40 Echogenic Intracardiac Focus. Apical four-chamber view
of a fetal heart with an echogenic focus in the left ventricle (LV). LA,
Left atrium; RA, right atrium; RV, right ventricle.
structure connected to the ventricle by a narrow channel. hese
oten do contract with the associated ventricle during systole. 209
Cardiomyopathy
Cardiomyopathy encompasses a diverse group of cardiac disorders
with variable etiologies and anatomic and functional characteristics,
and all result in an alteration in cardiac function. Cardiomyopathies
account for 8% to 11% of fetal cardiovascular
disease, 210 but only 1.8% of CHD in live-born infants. 154 Approximately
one-third of fetuses with cardiomyopathy die in utero,
which accounts for the diference in these numbers. 211
A variety of conditions can cause fetal cardiomyopathy (Fig.
37.41), including viral and bacterial infections, inborn errors of
metabolism, endocardial ibroelastosis, familial cardiomyopathy,
and maternal diabetes. Infectious agents act by damaging
the myocardium and producing a myocarditis with resultant
cardiomyopathy. 212 In the setting of storage diseases, the myocardium
becomes hypertrophic secondary to the accumulation
of various products within the myocardial cells. Many cases are
idiopathic. 213
Endocardial ibroelastosis (EF) is a poorly understood process
in which difuse endocardial thickening develops in one or more
cardiac chambers. EF is divided into two broad categories, primary
and secondary. Primary or isolated EF occurs in the absence of
other structural cardiac anomalies. In primary EF the afected
ventricle may be dilated or constricted. 214 Viral myocarditis is
thought to be the cause of primary fetal EF, with mumps and
coxsackievirus B the most common infections. 213,214 Secondary
EF occurs in the setting of a structural cardiac anomaly and
usually results in dilation of the afected chambers. he dilated
form occurs with coarctation of the aorta, aortic valvular
disease, mitral valvular disease, and other lesions. he less
common constricted form is associated with aortic stenosis or
atresia. In both types of EF the mural endocardium is largely
replaced by collagen and elastic tissue, giving it a glistening-white
appearance grossly 213 and a striking echogenic appearance at
echocardiography (Fig. 37.42).
An increased incidence of asymmetrical septal hypertrophy
(ASH) or concentric hypertrophy has long been recognized
in infants of diabetic mothers. 215 he characteristics of
these types of cardiomyopathy have been well documented
echocardiographically. 215-218 Overall cardiac size in fetuses of
diabetic mothers can be increased as a result of the hypertrophy. 219
Fetal hypertrophic cardiomyopathy can be expected in about
20% of pregnancies with pregestational diabetes and appears to be
associated with an elevated third-trimester maternal hemoglobin
A 1c and with an elevated neonatal insulinlike growth factor-1
(IGF-1) level. 220 Regardless of the cause, severe cardiomyopathy
results in decreased cardiac function and a tendency to develop
congestive heart failure. his may be secondary to obstruction of
ventricular emptying in obstructive forms of cardiomyopathy or to
pump failure in nonobstructive forms. he sonographic diagnosis
of obstructive cardiomyopathy depends on the demonstration of
hypertrophy of the ventricular wall or septum. Nonobstructive
cardiomyopathy can be diagnosed by demonstrating dilation
of one or more cardiac chambers along with poor ventricular
contractility. About 37% of live-born infants with cardiomyopathy