Fetal Heart (Ch. 51 & 35)

fetal heart

• heart lies in mid chest, slightly to the left

• ventricles (2)

  • located anteriorly and inferiorly

• atria (2)

  • located posteriorly and adjacent to base of heart

apex of the heart is normally tilted to the ____

left

true/false: RV is more anterior than LV

true

which heart chamber is closest to the spine?

left atrium (LA)

what are the 3 “doors” (shunts) in fetal heart circulation

1. ductus venosus

2. foramen ovale

3. ductus arteriosus

RA (right atrium)

• receives a mix of oxygenated and deoxygenated blood from IVC and SVC

• sends blood to RV through the tricuspid valve

• portion of oxygenated blood is shunted through foramen ovale into LA

  • SONO: jet of color shooting from RA to LA (small opening b/w RA and LA)

RA receives what type of blood and from where?

mix of oxygenated and deoxygenated blood; from IVC and SVA

RV (right ventricle)

• receives deoxygenated blood from RA

• has a moderator band within it

• normal: sends deoxygenated blood out through the main pulmonary artery to the lungs

• fetus: blood gets shunted away from lungs by ductus arteriosus that connects MPA to AO)

  • ductus arteriosus connects MPA to AO—this allows blood to skip the lungs and go directly into systemic circulation

RV receives what type of blood and from where?

deoxygenated blood; from RA

LA (left atrium)

• receives blood from pulmonary veins (some) and foramen ovale (most)

• sends oxygenated blood to LV via bicuspid/mitral valve (b/w LA and LV)

LA receives what type of blood and from where?

oxygenated blood; from foramen ovale and pulmonary veins

LV (left ventricle)

• receives oxygenated blood from LA

• sends oxygenated blood to the body via AO ← LVOT

LV receives what type of blood and from where?

oxygenated blood; from LA

foramen ovale

• opening between RA and LA

• oxygenated blood bypasses fetal lungs

• alows oxygenated blood from placenta (mother) to pass directly into LA

normal fetal HR in 2nd/3rd trimester?

between 120-160 bpm

brachycardia HR in 2nd/3rd trimester?

less than 100 bpm

tachycardia HR in 2nd/3rd trimester?

more than 200 bpm

fetal lie

• determine fetal lie and rotation

• used to ensure heart is. incorrect position and orientation

• fetal lie:

  • vertex

  • breech

  • transverse

• fetal rotation:

  • supine

  • prone

  • RT/LT side up or down

what does situs refer to?

how the organs are arranged in the fetus

normal situs

• heart on left

• stomach on left

dextracardia

• heart on right

• stomach on left

situs inversus

• heart on right

• stomach on right

T/F: LA is closest to the spine and AO

true

T/F: RV is most anterior to fetal body

true

situs?

normal situs

situs?

dextrocardia

5 heart views sonographers get

• 4-chamber heart

• LVOT (left ventricular outflow tract)

• RVOT (right ventricular outflow tract)

  • can get in long axis or short axis

• 3 vessel-view

• 3 vessel-trachea view

US evaluation of 4-chamber heart

• make note of right and left side

• lung should be seen on both sides of the heart

• ensure no fluid or masses seen adjacent to/around the heart

• LA is closest to AO and spine

• foramen ovale opens between RA and LA

• note symmetry between atria and ventricles

• tricuspid valve is on right side (b/w RA and RV)

• bicuspid/mitral valve is on left side (b/w LA and LV)

imaging the 4-chamber heart

• obtained from TRV view of abdomen just above diaphragm

• make sure to have ribs on both sides during 4CH view

  • must see ribs on both sides to be true TRV rather than oblique

• heart takes up 1/3rd of chest

• heart angles 45 degrees to the left

• always make sure the heart is beating