Cardiac Embryology, CHD terms, pediatric views Flashcards
(26 cards)
Cardiac Embryology timeline:
Days 18-19
Days 20-21
Days 23-28
Weeks 4-6
Week 6
Week 20
Days 18-19: Cardiogenic area near fetus head
Days 20-21: 2 strands fuse to become primitive heart tube (has heart beat)
Days 23-28: Heart elongates and twists (D-looping)
Weeks 4-6: Cardiac septation (valves form from endocardial cushions, formation of IAS and IVS)
Week 6: heart is fully formed but continues to grow
Week 20: muscle tissue fully formed
What are the regions of the heart tube, starting from head to tail?
truncus arteriosus
bulbus cordis
primitive ventricle
primitive atria
sinus venosus
What does each part of the heart tube become?
truncus arteriosus
bulbus cordis
primitive ventricle
primitive atria
sinus venosus
truncus arteriosus - Ao and PA
bulbus cordis - RV
primitive ventricle - LV
primitive atria - Both atria (and appendages)
sinus venosus - IVC and SVC
How does the IVS form?
Starts at apex and grows superiorly until it fuses with endocardial cushions
How does the IAS form?
(Atrial septation)
Septum primum grows inferiorly (hole is ostium primum)
Septum primum fuses with endocardial cushions and foramen secundum opens
Septum secundum grows beside septum primum. The two fuse and the foramen ovale remain open (flap valve)
Fetal circulation: changes at birth?
Foramen ovale closes - fluid forced out of lungs during birth and right sided pressures drop
Ductus arteriosus closes - blood flow changes direction bc pressures change and hormones
Levoposition
Midposition
Dextroposition
Cardiac position - apex still points left, heart shifts (age/tumor)
Levoposition - most ppl
Midposition - heart shifted a bit right
Dextroposition - heart shifted a lot right
What does situs mean?
situs means sidedness - is an organ sitting normally or flipped?
How is situs determined?
from the SC view: what direction does the apex point
if dextrocardia, roll patient to right side…
Levocardia
heart normal
Dextrocardia
heart flipped backwards
situs solitus
situs solitus totalis
everything normal
situs inversus
everything flipped
situs ambiguous
situs indeterminatus
random, a mix of normal and flipped organs
2 types
Dextroversion
Levoversion
Dextroversion
Dextroversion =
situs solitus (Abd organs normal) with dextrocardia (heart flipped)
Levoversion
Levoversion =
situs inversion (Abd organs flipped) with levocardia (heart normal)
Atrial situs solitus
Atrial situs inversus
Atrial situs ambiguous
Atrial situs solitus - atria normal
Atrial situs inversus - atria flipped
Atrial situs ambiguous
- 2 LAs (LA isomerism) or
- 2 RAs (RA isomerism - plus 2 right lungs and no spleen?)
Pediatric views: Ductal view
high left PLAX
see heart, PA, and DA elongated below the heart
PDA?
(coarc?)
Pediatric views: RVOT view
from SC LAX, rotate 45 counterclockwise and angle ant
RVOT?
MPA and bifuration?
Pediatric views: SSN crab view
from SSN, rotate 60 clockwise
All 4 PVs return to LA?
Assess SVC?
Pediatric views: SSN Arch position
from SSN crab, rotate further clockwise and angle to opposite shoulder
Left arch (on screen) - normal = 1st branch (BCA) to patients right
Right arch - abnormal = 1st branch to patients left
What happens if the heart tube loops the wrong way (L-looping)?
ccTGA (L-TGA)
(LV and RV are in the wrong spot but normal pathway)
What happens if the septum primum fails to fuse with the endocardial cushions?
ostium primum septal defect
What happens if the truncus arteriosus splits, but fails to spiral?
TGA (D-TGA)
