Endocardial Cushion Defects

Question 1

Endocardial Cushion defects are a result of what?

Answer 1

Growth failure in the development of the atrioventricular endocardial cushions.

Question 2

What is another name for endocardial cushion defect?

Answer 2

Partial or Complete AV canal defect

Question 3

How do the endocardial cushions grow?

Answer 3

Convex towards the atria and IAS

Concave towards the ventricles and IVS

Question 4

Endocardial cushion defects, ASD’s, and VSD’s are common in babies born with _____ ________.

Answer 4

Down’s Syndrome (Trisomy 21)

Question 5

The endocardial cushions help form ____, ____, ____, ____, and ____.

Answer 5

Interatrial septum, Interventricular septum, anterior leaflet of Tricuspid valve, part of septal leaflet of Tricuspid valve, and anterior leaflet of Mitral valve.

Question 6

A complete AV canal involves ______________.

Answer 6

All 4 valves and chambers.

Question 7

A complete AV canal may also have a ________ and a ________.

Answer 7

Large membranous VSD and a large primum ASD.

Question 8

With a complete AV canal, the ____ and ____ can be merged so there is _____________.

Answer 8

Mitral valve
Tricuspid valve
Just one valve

Question 9

With complete AV canal, there can be _______, the __________ is usually incompetent, and there can be _____________.

Answer 9

Shunting at both levels
Aortic valve
Aortic insufficiency

Question 10

Some associated defects with complete AV canal are: (6 examples)

Answer 10

Primum ASD, fenestrations, sinus venosus ASD, VSD, cleft Mitral valve

Question 11

What is a partial AV canal?

Answer 11

When the endocardial cushions partially fuse resulting in the division of the av canal into R/L atrioventricular ostia.

Question 12

Associated with partial AV canals are: a)____ b)____ c)____ d)____

Answer 12

a) R/L ostium b) Primum ASD c) cleft in anterior leaflet of MV d) RV volume overload

Question 13

What type of shunting is there with complete AV canal?

Answer 13

Shunting at both levels. 4 chamber mixing.

Question 14

In complete AV canal defects, the aortic valve is usually _______ and there can be _____ _______.

Answer 14

Incompetent

Aortic Insufficiency

Question 15

Due to the 4 chamber mixing, O2 sats are probably in the ___ and baby may be a bit _______.

Answer 15

80’s

Cyanotic

Question 16

With complete AV canal defects the ____ ____ and _____ _____ may be malformed or not formed at all.

Answer 16

Mitral valve

Tricuspid valve

Question 17

Associated defects with complete AV canal defects:

Answer 17

Other types of ASD or fenestrations, VSD, cleft mitral valve

Question 18

How are partial AV canal defects formed?

Answer 18

Endocardial cushions partially fuse resulting in the division of the AV canal leaving a right and left ostium.

Question 19

Associated defects of partial AV canal are:

Answer 19

Primum ASD, cleft in anterior leaflet of mitral valve, possibly VSD.

Question 20

What happens to the RV in partial AV canal defects?

Answer 20

There is an RV volume overload due to the RA volume overload.

Question 21

How does a volume overload affect the RV?

Answer 21

The RV chamber will dilate over time, become hyperdynamic, and pressures will increase.

Question 22

Why is there a fixed/split S2?

Answer 22

It’s all the same. Pressures are the same throughout.

The time interval between the A2 and P2 are fixed unlike the variable physiologic split found in a healthy heart.

Question 23

What would produce a thrill?

Answer 23

High volume going out the PA can produce a palpable thrill.

Question 24

Clinical findings for ECD’s: (10 examples)

Answer 24

Fixed/split S2, thrill, failure to thrive, fatigue, dyspnea, PHTN, growth retardation, CHF, decreased O2 sats, difficulty maintaining a stable BP

Question 25

What does the 4 chamber mixing lead to?

Answer 25

RAE, LVE, RVE, RV volume overload

Question 26

If a baby has ECD’s but is not ready for surgery, what palliative measure can be taken and why?

Answer 26

PA banding. This will reduce flow rate to the lungs, protecting them from risk of increased pulmonary vascular resistance.

Question 27

Is the fixed/split S2 the only murmur?

Answer 27

There can be regurgitant murmurs as well. But with all of the swirling of flow, heart sounds may be difficult to distinguish.

Question 28

Why do small defects sometimes go unnoticed?

Answer 28

No big changes in O2 sats. Baby can grow normally showing few symptoms. EKG and chest xray can look normal. Murmur may be mild.

Question 29

What is the baby’s prognosis if ECD is not repaired (usually) within the first year?

Answer 29

Mortality rate is high. About 80% at 2 years due to increasing CHF and pulmonary vascular disease.

Question 30

What is the goal of surgical repair?

Answer 30

To restore normal circulation by closing the ASD or VSD with patches. (these are too large for occluder devices)

Question 31

Some surgical repairs for ECD’s include: (4 examples)

Answer 31

Reconstruct or replace TV and MV.
Remove PA band and any other palliative measures. Replace Ao valve if abnormal or incompetent.
Repair any other defects, ex:coarctation or RVOT obstruction.

Question 32

Why would it be beneficial to postpone surgery if baby is stable enough?

Answer 32

It gives the pericardium time to thicken and strengthen for use in repairing defects.

Question 33

What might be used to repair ECD’s?

Answer 33

Baby’s own pericardium or gortex grafts