Diagnostic ultrasound ( PDFDrive )

1286 PART IV Obstetric and Fetal Sonography
Ebstein anomaly
RA
LA
RV
LV
Tricuspid
valve
Mitral
valve
LA
RA
A
Anterior
B
FIG. 37.28 Ebstein Anomaly. (A) Diagram showing the tricuspid valve apically displaced, resulting in an enlarged right atrium (RA) and a small,
functional right ventricle (RV). (B) Gray-scale image shows tricuspid valve (arrow) displaced inferiorly, resulting in an “atrialized” RV and enlarged
RA. See also Video 37.12. LA, Left atrium; LV, left ventricle.
closely associated with fetal hydrops and a worsening prognosis. 79
Frequently, a let ventricular–to–right atrial jet can be identiied
across the ostium primum defect before the onset of holosystolic
valvular insuiciency. 38 Cardiac malformations associated with
AVSD include septum secundum ASD, hypoplastic let heart
syndrome (HLHS), valvular pulmonary stenosis, coarctation of
the aorta, and tetralogy of Fallot (TOF). A meta-analysis of
published cases of AVSD diagnosed prenatally conirmed that
chromosomal anomalies are common, occurring in 25% to 58%
of afected fetuses. 80 herefore karyotyping is indicated. Associated
extracardiac anomalies are common, including omphalocele,
duodenal atresia, tracheoesophageal atresia, facial clets, cystic
hygroma, neural tube defects, and multicystic kidneys. 80
he fetus with an AVSD and associated defects has a poor
prognosis. When hydrops is present, few survive the neonatal
period. 81 Despite advances in pediatric cardiothoracic surgery,
the overall outcome for antenatally diagnosed AVSD remains
variable, with many studies reporting 5-year to 15-year survival
rates below 50%. 80,82 Others have reported excellent long-term
results with newer surgical techniques such as the two-patch
technique with early complete clet closure for complete AVSD
repair. 83
Ebstein Anomaly
Ebstein anomaly is characterized by inferior displacement of the
tricuspid valve, frequently with tethered attachments of the
lealets, tricuspid dysplasia, and right ventricular dysplasia 84-88
(Fig. 37.28, Video 37.12). Ebstein anomaly makes up approximately
7% of cardiac anomalies in the fetal population and has
an incidence of 0.5% to 1% in high-risk populations. 64,89,90 It
occurs in approximately 1 per 20,000 live births. 91
Early data from biased retrospective studies suggested that
lithium use during pregnancy was associated with an estimated
500-fold increase in the incidence of Ebstein anomaly in
exposed fetuses. 91-96 It is now clear that the increased risk is
less than 2%. 45,97 Ebstein anomaly may be associated with a
variety of structural cardiovascular defects, particularly pulmonary
atresia or stenosis, 98 arrhythmias, and chromosomal
anomalies. 86,99-102
Ebstein anomaly is readily detected in utero. 99,103 he sonographic
diagnosis rests on recognition of apical displacement of the
tricuspid valve into the right ventricle, an enlarged right atrium
containing a portion of the “atrialized” right ventricle, and a
reduction in size of the functional right ventricle. Diferential
diagnosis includes tricuspid valvular dysplasia, Uhl anomaly,
and idiopathic right atrial enlargement, but none of these has
an inferiorly displaced tricuspid valve, the most reliable sign of
Ebstein anomaly. Ebstein anomaly is one of the few structural
defects that may cause substantial cardiac dysfunction in utero,
frequently with cardiomegaly, hydrops, and tachyarrhythmias. 86
Examination with spectral and color Doppler ultrasound is
helpful in demonstrating tricuspid valve regurgitation, which
causes further enlargement of the right atrium and ventricle. 104
Tethered distal attachments of the tricuspid valve, marked right
atrial enlargement, and let ventricular compression with narrowing
of the pulmonary outlow tract are all associated with a
poor prognosis. 86 Fetuses diagnosed with Ebstein anomaly and
tricuspid dysplasia have a poor prognosis, with an overall perinatal
mortality (fetal demise or death before neonatal discharge)
of 45%. 105
Arrhythmias, particularly supraventricular tachycardias
(SVTs), are common with Ebstein anomaly and can further
compromise the fetus. Overall, the 3-month mortality rate for
patients diagnosed in utero is 80%. 86,103 Surgical correction of
Ebstein anomaly in young children is associated with a low
mortality rate and an excellent quality of life. 106-108 Because clinical