M1: Basic Embryology and Septal Defects Flashcards

1
Q

when in wks in the heart formed

A

3-7 wks gestation, first organ to develop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

in what wk does the echogenic area of the heart appear and what is it called

A

wk 3

cardiogenic area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

when the heart is just an endocardial tube, what direction does blood flow

A

unidirectional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how do the two heart tubes form the heart

A

they fuse into one tube and then twist/loop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does looping of the heart accomplish

A

transforms the single heart tube into a more complex structure with 2 atria and 2 vent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how does the heart normally loop (which direction)

what direction is abnormal heart looping and what does it lead to

A

normal looping is rightwards… heart tube folds to the right

left - left transposition of the great vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the trunks arteriosus and what does it form

A

structure near the superior aspect of the heart

forms the semilunar valves, the AO root and PA form as the trunk separates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

order of formation of the atrial septum and structures

A

septum primum
foramen secundum
septum secundum
foramen ovale valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the septum primum and how it forms

A

divides the atria into L and R

extends down from the roof of the common atria towards the endocardial cushions… creates the foramen primum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the the foramen primum

A

opening b/w atria formed by the septum primum and located at its lower margin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe the foramen secundum and how it forms

A

tissue that grows inferiorly towards the endocardial cushions and closes the foramen primum

perforations appear in the upper portion of the septum primum which form the foramen secundum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe the septum secundum and how it forms

A

tissue that grows inferiorly to the right of the septum primum and partially overlaps the foramen secundum which forms the foramen ovale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

after the foramen ovale is initially formed, what keep the flap patent

A

increased RAP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the foramen ovale valve and how it forms

A

the upper septum primum disappears and the lower part of the septum primum becomes the valve of foramen ovale and the septum secundum starts growing superiorly for the AV cushion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what happens to the foramen ovale at birth

A

increased systemic and vascular resistance paired with decreased RAP causes LAP to rise over the RAP

this pushes the valves of the foramen ovale against the septum secundum and closes the hole (they should eventually fuse after a few weeks)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

5 types of ASDs

A
ostium primum
ostium secundum
sinus venosus
coronary sinus
PFO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe an ostium primum ASD

what is it associated with

A

ASD located in lower atrial septum, 15 % of cases

cleft anterior MVL
atrioventricular canal defect
T21

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe an ostium secundum ASD

what is it associated with

A

ASD located mid atrial septum, 80% of cases

usually isolated
MVP
pulmonary stenosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe a sinus venosus ASD

what is it associated with

A

can be superior or inferior, where the IVC and SVC enter the RA, 6% of cases

anomalous pulmonary venous drainage (into RA instead of LA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

describe an coronary sinus ASD

what is it associated with

A

when the root of a CS is missing in both the LA and RA, creating a hole in the IAS, <1 %

persistent left SVC
total anomalous pulmonary venous return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

3 steps in ventricular septal formation

A

1 trabecular IVS formation
2 TV orifice and MV orifice formation
3 truncus formation
4 membranous IVS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe trabecular IVS formation

how does it grow

A

the bulbs cords becomes the RV and the primitive ventricle becomes the LV…

grows from apex to base but stops part way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does the trabecular IVS stop growing part way

A

to allow blood from both ventricles to exit the truncus arteriosus through the inter ventricular foramen (IVF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

is the trabecular IVS the membranous or muscular portion

A

muscular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
describe TV orifice and MV orifice formation formation how does it grow
the truncus arteriosus and AV canal move more centrally and the orifices are formed through the growth of the inlet portion of the IVS
26
the fusion of which two structures forms most of the IVS
the inlet and trabecular IVS
27
describe the truncus formation
this structure divides with the formation of the conotruncal septum to form the prox AO and prox pulmonary A.... forms in a spiral fashion
28
more specifically, how do the AO and PA roots form
the conus cordis divides the outflow tract into R and L two swellings in the truncus arteriosus begin to grow which form a septum and divides the truncus into AO and PA
29
what is the conus cordis
superior part of the RV
30
describe the membranous IVS formation
after the TA is divided, the membranous septum forms to complete the R and L heart septation sequence
31
4 locations for VSD and their prevalence
muscular 10-20 % membranous/paramembranous 70-80% inlet septum 5% outlet septum 5%
32
another name for outlet VSD another name for inlet VSD
-infundibular VSD ....infundibulum is the ridge of muscle b/w the LVOT and RVOT -atrioventricular canal
33
2 types of outlet VSDs explain their location
supracristal and infracristal there's a ridge of smooth muscle in the RVOt called the crista supraventricularis - supracristal VSDs are above the ridge - infracristal VSDs are below the ridge
34
describe where you would see supracristal, infracristal and paramembranous VSDs in PSAX
AO zoom, supra- coming straight up infra - going to the right of the image toward the PA paramembranous - going to the left of the image towards the TV
35
what type of congenital heart defect is a VSD what does this mean
normally it is an acyanotic congenital defect means it not bad enough to cause serious hypoxia
36
in which direction does blood travel with a VSD and ASD
from left to right due to high left heart pressure... in fetus is goes from right to left.
37
what tool is used to assess a shunt of any kind (PDA, ASD, VSD)
Qp/Qs
38
study photos in notes for locations of ASDs/VSDs in various echo views
/
39
what does Qp/Qs represent
Q= volume of flow... volume of flow in the pulmonary circulation / volume of flow in the systemic circulation
40
how is Q/the volume of flow determined
by measuring the stroke volume at two intracardiac sites...
41
how to do Qp/Qs for a ASD and VSD
find the stroke volume of the pulmonary artery using RVOT diameter and VTI of the PW of the RVOT ( pie(r)^2 x VTI ) then do the same with the LVOT and divide these values you can technically do this with any valve in the heart so could use the TV for Qp and MV for Qs
42
what does Qp/Qs equal in a normal heart
1:1 because flow through the R and L sides are equal
43
what Qp/Qs values indicates a hemodynamically significant shunt
Qp/Qs of > 1.5:1
44
Qp/Qs ratio for small and large shunts
small: 1 or 1.5:1 large > 2:1
45
treatment for small, med and lrg shunts
sm: none or septal occlude device md: septal occluder device or septal patch lrg: usually septal patch
46
how are septal occlude devices deployed
intravenously
47
how are septal patchs deployed
open heart surgery
48
with a VSD, how can the increased flow effect the RV and LA
they may dilate
49
how is doing Qp/Qs different for a PDA why
for a PDA, the Qp is derived from the LVOT and the Qs is derived from the RVOT.... we want to measure flows after they have travelled through the pulmonary and systemic circulation. after the blood exits the LVOT, it travels to the MPA through the PDA then to the lungs.... we switch the values because the flow in greater in the L heart so Qs will be larger than Qp in this case
50
which side of the heart does a PDA cause increased volume
left heart ONLY (VSD and ASD are both the R and L)
51
explain the flow of blood with a PDA
blood in the ascending Ao is shunted to the MPA through the PDA, then the extra volume goes through the lungs and the PVs to empty into the LA, LV and AO again. then the cycle continues
52
explain the flow of blood with a ASD
blood is shunted from the LA to the RS, into the RV, P valve, lungs, PVs and into the LA, then back to the R heart
53
explain the flow of blood with a VSD
blood is shunted from the LV to the RV, then the P valve, lungs, PVs and LA, LV again and back to the R heart.
54
how do you calculate the RVSP with a VSD
RVSP = Systolic BP of the arm - ( 4 x (max velocity of the VSD)^2) ) second half of the equation will give you the change in pressure b/w the ventricles
55
are VSDs in adult usually small avg velocity
yes 5-6 m/sec
56
what happens to the heart if the VSD is large
Eisenmengers will occur
57
what is Eisenmengers syndrome why does it happen
when the direction of a shunt is switched to go right to left due to a large shunt in the heart that has high volume passing through it going to the lungs, causing lung damage and scarring over time... ... which causes irreversibly high pulmonary vascular resistance and severe pulmonary hypertension.
58
6 complications of Eisenmengers
``` CHF early death Brain abscess SBE - bacterial endocarditis pulmonary infarction pregnancy is contraindicated w/ Eisenmengers, extra volume would be too much for the heart, mom would likely die ```
59
how should you describe intracardiac shunts when reporting
segmental approach, then describe actual name of the defect
60
do you have to interrogate every heart for a shunt
yes
61
2 functions of the endocardial cushion
1 divides the AV canal into 2 atrioventricular orifices | 2 assist in closure of ostium primum portion of IAS and membranous portion of IVS
62
what are the 4 endocardial cushions
2 medial cushions | 2 lateral cushions
63
what do the 2 medial endocardial cushions form how does they grow
form the: septal leaflet of the TV, anterior leaflet of the MV and part of the inflow perimembranous inter ventricular septum grow from laterally from mid-line
64
what do the 2 lateral endocardial cushions form how does they grow
form the: anterior and posterior TV leaflets and the posterior MV leaflet grow from medially from the sides
65
how many sets of Ao arches originally for in the fetus
6 sets, most are absorbed into the body
66
which AO arch in the fetus forms the adult AO what do the others form into
4th Ao arch carotid and ductus arteriosus
67
what forms the AV valves
formed from the partition of the AV canal and the lateral endocardial cushions... AV valves made of connective tissue
68
what forms the SL valves
the truncus arteriosus, swelling of tissue forms the valves
69
normal route of fetal circulation stating at umbilical vein
umbilical vein > ductus venosus > IVC > RA, then the eustachian valve directs more of the blood through the foramen ovale but there are two other paths: 1) RV>PA>...LA>LV>AO 2) RV>PA>...DA>A
70
function of the eustachian valve
directs fetal blood through the foramen ovale
71
why does very little blood go through the pulmonary circulation in the fetus
fetal lungs have very high resistance vascular beds
72
how does the fetal circulation pathway change at birth
- umbilical vein closes - ductus arteriosus closes and become the ligamentum arteriosum - ductus venosus closes and becomes the ligamentum venosum - foramen ovale closes and becomes the fossa ovalis (indent where the hole was located) - RV and PA walls decrease in thickness and LV wall increase in thickness. because pressure in R heart goes down and L heart goes up
73
2 most common locations for congenital heart defects
ductus arteriosus and foramen ovale