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The tricuspid
and mitral valves of the heart are attached to
small papillary muscles within the heart by fibrous strands
called the chordae tendineae. The papillary muscles act to
stabilize the valves when the ventricles contract.
Echogenic intracardiac foci (EIF) or "bright spots" in the
heart are believed to be caused by an increased reflection of
sound off the small papillary muscles or chordae tendineae.
These bright spots are most often a normal variant and have
no significant effect on the development of the heart. EIF
may be seen in up to 30, 6, and 11 % of Asian, black, and
white fetuses respectively [1]. EIF are found in 13 to 18%
of fetuses with Down syndrome [2]. Ultrasound findings
that occur more commonly in fetuses with Down syndrome
are called markers.
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Click image to enlarge |
The isolated finding of an EIF
appears to increase the likelihood of
Down syndrome by 1.8 to 2.8 times
[3, 4] according to two studies.
However, one study found that an
isolated EIF in the fetal heart in women aged 18-34 years was not associated
with increased risk for Down syndrome [5].
Presently genetic testing of the
fetus (amniocentesis) is offered in California if the risk of Down syndrome in the fetus
is 1 in 190 or greater. As the table below illustrates for a woman less than
32 years of age at delivery the finding of an echogenic focus does not
increase the likelihood of Down syndrome enough to recommend routine
amniocentesis.
|
Maternal Age At Delivery |
Midtrimester Risk of Down Syndrome Based on Maternal Age |
Risk of Down
Syndrome
Based on
Maternal Age
With EIF |
| 30 |
1 in 700
|
1 in 250 |
| 31 |
1 in 613 |
1 in 219 |
| 32 |
1 in 526 |
1 in 188 |
For women 32 years of age at
delivery the increased likelihood of
Down syndrome, by some reports,
would be sufficient enough to offer
amniocentesis.
If an echogenic intracardiac focus is found on routine ultrasound then a
targeted level II sonogram is usually recommended.
- To distinguish an
EIF from a
fetal cardiac tumor.
Fetal cardiac
tumors are most commonly
found within the cardiac muscle
or septum. Cardiac tumors tend
to be larger, multiple, and are not
as echogenic as the typical
"echogenic focus"
- To identify
additional markers
for Down syndrome if present.
The use of the EIF as a marker
for Down syndrome in the fetus of
an Asian mother is questionable
due to the increased frequency of
EIF as a normal finding in the
Asian population.
- In non-Asian
populations genetic
testing of the fetus
(amniocentesis) may be
recommended with detection of
an isolated EIF, if serum
screening (ExAFP) indicates a
risk for Down syndrome greater
than or equal to 1 in 531 or the
patient is 32 years of age or
older at delivery.
REFERENCES
1. Shipp TD, et al. The frequency of the
detection of fetal echogenic intracardiac foci
with respect to maternal race. Ultrasound
Obstet Gynecol. 2000 ;15:460-2. PMID: 11005111
2. Bromley B, et al Significance of an
echogenic intracardiac focus in fetuses at
high and low risk for aneuploidy.J Ultrasound
Med. 1998;17:127-31. PMID: 9527573
3. Nyberg DA, et al . Isolated sonographic
markers for detection of fetal Down
syndrome in the second trimester of
pregnancy. J Ultrasound Med. 2001;20:1053-
63. PMID: 11587012
4 . Smith-Bindman R, et al. Second-trimester
ultrasound to detect fetuses with Down's
syndrome. JAMA 2001;285:1044-55 PMID: 11209176
5. Anderson N and Jyoti R Relationship of
isolated fetal intracardiac echogenic focus to
trisomy 21 at the mid-trimester sonogram in
women younger than 35 years.Ultrasound Obstet Gynecol. 2003 ;21:354-8. PMID: 12704743
Created: 6/1/2004
Updated 5/25/2007
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