C8.1 Norm Fetal Heart Anatomy Flashcards
When does the heart tube begin to develop and when is it fully formed? From what tissue does it develop from
- starts to develop at 5 wks, fully formed by 10th wk
- develops from mesoderm
When do we routinely scan the fetal heart?
When is it best been?
From 18wks to term (40 wks)
-b/w 18-24 wks
When does the heart start beating
22-2 days post conception
What are the 3 structures in the heart that are specifically to fetal circulation?
-ductus venosus
+ umbilical vein
-foramen ovale
+ shunts blood from RA to LA (1/2 of the blood crosses to LA and 1/2 to PV)
-ductus arteriosus
+ connects the PV and the AO
What’s another name for the umbilical arteries?
Do they carry high or low O2 blood?
Hypogastric arteries
Low 02
Describe the position of the heart in the fetal chest
- horizontal
- left of midline (compare to the stomach)
- apex is 45 degrees to the L
- takes up 1/3 of chest
Which chamber of the heart if most anterior and which is most posterior
LA is most posterior
RV is most anterior
What is the moderator band used to prove?
-used to prove which chamber is the RV in abnormal hearts
What are we looking for when assessing the AV/LVOT?
Looking to see that the wall of the AV is continuous with the IVS
Which structure is more anterior? The PA of the AO?
PA
What’s the function of the ductus arteriosis
Shunts blood from the PA to the AO arch to bypass the lungs
-should close after delivery
What is the foramen ovale?
- Opening b/w the atria, the ovale flap opens into the LA
- also helps bypass the lungs
What are the routine images of the heart?
4 chamber LVOT RVOT 3 vessel view Cine clip (Sometimes) Fetal heart M-mode
How should the LVOT and the RVOT be located in relation to one another?
LVOT and RVOT should cross each other
What does the 3 vessel view show
SVC
PA
AO arch
What does the 12sec cine clip show? Where does it start and end
Starts at the level of the AC showing fetal stomach…
… then shows 4 chamber view, LVOT, RVOT and 3 vessel view… sweep all the way up tp fetal neck
How do you do an M mode tracing of the fetal heart?
Place the cursor through the heart crossing both the atria and the ventricles to check for heart block
-usually record only 1 beat
What is a norm HR?
What value is concerning?
120-160
- <100 in 1st trimester is concerning and <100 in 2nd or 3rd trimester is bradycardia
- up to 180 in 3rd trimester can be normal…. >200 is tachycardia
What are the additional images that we take of the heart?
- short axis
- SVC- IIVC w/ RA (long horn view)
- AO arch
- Ductal Arch
- PV w/ LA
What are we looking for when looking at the AO Arch?
Look for coarchtation of the AO…. narrrowing of the AO arch
What does the ductal arch view show
The RV joking the AO (hockey stick appearance)
What are techniques you can use to enhance the visualization of the heart
- sector down
- zoom up
- decrease dynamic range
when assessing the 3 vessel view, if the circle in the middle is small what does this tell us
theres an abnormality of the L heart
when assessing the 3 vessel view, if the circle on the left is small what does this tell us
theres an abnormality of the R heart
