M12: FetalCardiac Abnormalities Flashcards
When does the heart begin to develop, when is it fully formed
5 wks
10 wks
Describe how the heart develops… when do the chambers of the heart develop
Paired heart tubes fuse to form a single heart
B/w 6-8 wks
When is a heart beat detected
5-6 wks
Describe the pathway of blood starting from the placenta
Placenta > umbilical vein > Lt portal vein > ductus venosus and some through the hepatic veins > IVC > RA > foramen of ovale > LA > LV > AO > iliacs > hypogastric A > umbilical A > placenta
Some blood also goes from the RA to the RV, through the PA, to the lungs, PV and to the left heart.
OR from the RV blood can go through the PA and ductus arteriosus to the AO
Do the umbilical V or A carry O2 rich blood
Veins
Number of umbilical artery and vein
2 arteries
1 vein
Most of the blood that does enter the RV will pass through which structure
The ductus arteriosus b/c blood is getting oxygenated from mom
What does the ductus venosus connect?
Ductus arteriosus?
DV: connects LPV to IVC
DA: PA to AO
indications for fetal echo
abnormal findings
fam HX of congenital heart disease
previous prog w/ cardiac abnormality
maternal disease associated w/ heart defects (type 1 diabetes)
1 reason for fetal echo
type 1 maternal diabetes
other findings associated w/ heart defects
2 vessel cord CDH omphalocele thick nuchal fold or NT (> 3.5 mm will do echo) hydrops chromo abnorm bradycardia
what % of T21 babies have heart defects
50%
fetal echo routine
which are done at detailed, which are fetal echo only
detailed: find situs w/ stomach and heart 4CH LVOT/RVOT 3 Vv
echo only: AO arch and ductal arch short axis of ventricles and atria SVC/IVC (long horn view) pulmonary veins
which chamber of the heart is most anterior
RV
how should the RVOT and LVOT cross
90 degrees
size of the structures in 3 vV
PA>AO>SVC
appearance of the AO arch and ductus venosus
AO: candy cane w/ great vessels
DA: hockey stick, no branches
in which views may you do doppler in a fetal echo
inflow
outflow
ductus arteriosus
foramen ovale
how do we do Mmode of the heart
why
insinuating through both the atria and ventricles
to rule out arrhythmias and heart block
when in wks is a fetal echo best performed
20 or 22 2ks to term
4CH view R/O what amount of cardiac defects
how about if we included outflows?
1/3
2/3
norm HR
what is considered bradycardia
tachy?
120-160… up to 180 in first trimester
Brady: <100 bpm
tachy: > 200 bpm (reduced SV)
what usually causes Bradycardia in fetuses
heart block
how is tachycardia of the fetus treated
digoxin to mom… moms heart will respond also
most common arrhythmia in a fetus
are they worrisome
PACs
not usually
describe an ASD
why is it hard to diagnose
partial or complete absence of the IAS
due to norm foramen ovale
how large should the foramen of ovale be
no larger than the AO root
how do you want the septum placed on the screen when looking for an ASD
horizontal
describe a VSD
partial or complete absence of the IVS, usually associated w/ other cardiac anomalies
MOST COMMON CARDIAC ANOMALY
best view to asses a VSD
subcostal/horizontal 4 CH and short axis of ventricles is best
prognosis for VSD
good, many close on their own if they’re small
how does blood move through the Foramen ovale
from RA to LA in the fetus
when does an atrioventricular septal defect (AVSD) occur
describe the abnormality
when the endocardial cushions fail to fuse early in embryology
1 common valve w/ 5 leaflets (combo of TV and MV)
describe the anatomy of the heart ear in embryology
starts as a common ventricle and common atria that communicate through the AV canal
another name for a AVSD
AV canal
endocardial cushion defect
what % of fetuses w/ T21 have an AVSD
50%
describe ebstein’s anomaly
US appearance
apical displacement of the TV into the RV
large RA
apical displacement of TV
sm/dysplastic RV
ebstein’s anomaly is associated w/ which other anomalies
hydrops
pulmonary stenosis
ebstein’s anomaly is associated w/ the ingestion of which medication
lithium
why does a hypoplastic Right ventricle occur
secondary to pulmonary atresia w/ no VSD.. theres no blood flow getting into the RV which makes it small
Us appearance of hypoplastic Right ventricle
difficult to see inner chamber and sm or absent pulmonary artery
why does a hypoplastic left ventricle occur
US appearance
due to decreased flow into or out of the LV
sm LV
AO stenosis or atresia
MV atresia
hypoplastic left ventricle is associated w/ which other anomalies
coarctation of the AO endocardial fibroelastosis (EFE) as preg progresses
RVOT, LVOT ratio
1:1
describe endocardial fibroelastosis (EFE)
cause
myocardium is replaced by collagen and elastic tissue which causes decreased cardiac function and congestive HF
muscle hypertrophy
when is endocardial fibroelastosis (EFE) seen
w/ hypoplastic heart syndromes
US appearance of endocardial fibroelastosis (EFE)
thick, echogenic myocardium
in general, what causes hypoplastic heart syndromes
lack of blood flow into or out of either of the ventricles, which doesn’t allow them to develop normally
4 abnormalities w/ tetralogy of fallot
VSD
AO overriding ventricular septum (too big)
hypertrophy of RV
pulmonary stenosis
describe truncus arteriosis
single large vessel arising from the base of the heart (PA and AO start as one didnt separate)
the single vessel w/ truncus arteriosis supplies which vessels/circulation
coronary arteries
pulmonary circulation
systemic circulation
US appearance of truncus arteriosis
VSD
larger overriding AO
pulm A origins will vary off the AO
will you have a separate ductal and AO arch w/ truncus arteriosis
no, only one vessel
describe double outlet RV
common anomaly w/ this condition
when the Ao & PA both arise form the RV
VSD
double outlet RV is associated w/ what maternal factors
maternal diabetes
alcohol abue
describe transposition of the great vessels
when the AO arises from the RV and the PA arises from the LV and both outflow vessels are parallel/dont cross at 90 degrees
2 types of transposition of the great vessels
complete/D loop:
D for dextro
corrected/L loop:
L for levo
describe a D loop/complete transposition
closed circuit where blood flows from RA to RV
not compatible with life
US appearance of D loop/complete transposition
great vessels parallel instead of crossing
maybe VSD
describe the direction/flow of blood w/ a complete transposition
De02 > RV > AO > body/head
02 > LV > PA > lungs
describe a L loop/corrected transposition
what to look for to identify the RV
when the RV is attached to the LA
moderator band
is pulmonary and systemic circulation normal with corrected transposition
yes
US appearance of corrected transposition
parallel great vessels
morphologic RV to LA
can people w/ corrected transposition be asymp
when might they start to show symptoms
yes
mid life, they might show signs of heart failure b/c the RV can’t cope w/ the pressure
describe the morphology of the PA and AO w/ corrected transposition
PA comes off the LV and de02 goes to lungs
AO off the RV and 02 goes to body…
basically the LV and the RV switch spots and everything else is normal
describe coarctation of the AO
narrowing of the AO lumen, usually at the isthmus (area b/w the Lt subcla A and the descending AO)
US appearance of coarctation of the AO
prominent RV
sm LV (not enough flow into/out of the LV and AO)
narrowing of the AO
coarctation of the AO is associated w/ which conditions
AVSD
VSD
maternal diabetes
when does coarctation of the AO often occur
after birth due to tissue from the ductus arteriosus entering the AO as it seals off
2 locations for coarctation of the AO
pre ductal and post ductal
most common cardiac tumor
Rhabdomyoma (cardiac hamartoma)
US appearance of Rhabdomyoma
solid echogenic tumors usually on the ventricular septum… may obstruct outflows
DDX for Rhabdomyoma
cardiac fibroma
hemangioma
myxoma
teratoma
describe cardiomyopathy
muscle damage that results in altered cardiac function
causes of cardiomyopathy
viral infection
bacterial infection
metabolic disease
maternal type 1 diabetes
what is ectopic cordis
associated w/ which condition
heart outside the chest cavity
pentalogy of central
describe cardiosplenic syndromes
which organs are affected
symmetrical development of normally asymmetric organs or organ systems…. fetus either has 2 left sides or 2 right sides
liver
lungs
stomach
heart
another name for cardiosplenic syndrome
isomerism
situ ambiguous
heterotaxia
describe polysplenia
US appearance
bilateral left sidedness…
multiple spleens (polysplenia) LA isomerism (2 LAs) 2 left lungs midline liver IVC interruption dextro or mesocardia
what happens to the IVC w/ polysplenia
IVC doesnt course through the liver and the HV empty into the RA… the renal and subhepatic segments drain into the azygous veins which drain into the IVC
describe dextro and mesocardia
dextrocardia: heart points to R side
mesocardia: heart in the middle of the chest
is Lt or RT isomerism better
LT
other names for bilateral right sidedness
asplenia
ivenmark’s syndrome
describe the anomalies of asplenia
no spleen right atrial isomerism (2 RAs) 2 right lungs midline liver bilateral SVC
possible heat defects seen w/ cardiosplenic syndromes.
asplenia/right isomerism
- transposition of great arteries
- pulm stenosis or atresia
- total anomalous pulmonary venous return (2 RA, normal LA)
- complete heart block
heart defect are much worse w/ asplenia
-AVSD is common w/ asplenia
which defects are associated w/ heterotaxia
almost any heart defects can be associated w/ it
diagnosing cardiosplenic syndrome on US
hard to diagnose
clues may be:
- interrupted IVC
- large azygous vein
- abnormal liver, stomach or heart position
which type of transposition is more common
D loop/complete
