Congenital Heart Defects: ASD/VSD- Topic 9 Flashcards
CPB Normorthermic Blood Flow
0-3 kg = 200 cc/kg/min 3-10 kg= 150 cc/kg/min 10-15 kg= 125 cc/kg/min 15-30 kg= 100 cc/kg/min >30 kg= 75 cc/kg/min >55 kg= 65 cc/kg/min
CPB Normorthermic Blood Flow
0-3 kg = 200 cc/kg/min 3-10 kg= 150 cc/kg/min 10-15 kg= 125 cc/kg/min 15-30 kg= 100 cc/kg/min >30 kg= 75 cc/kg/min >55 kg= 65 cc/kg/min
Atrial Septal Defects most commonly occur as defects in what?
Septum primum within the fossa ovalis (secundum ASD)
Atrial Septal defects CAN involve the secundum near what?
SVC
sinus venosus defects are less common
Atrial septal defects will do what to physiology?
Will cause pressure mediated shunting
L to R
R to L
Which shunt is of most concern to you? L to R or R to L?
R to L; skips the lungs; cyanotic shunts
*BUT both are of concern; one can become the other because it is pressure mediated
How is blood flow quantitated? (In shunts)
Pulmonary Blood Flow (Qp)
Systemic Blood Flow (Qs)
What would expect the Qp/Qs ratio to be in a normal individual?
1 (1:1 ratio)
When do shunts require treatment?
When they are symptomatic
When do shunts require treatment?
When they are symptomatic
Pulmonary over circulation
Shunts causing increase in right heart size
When do shunts require treatment?
When they are symptomatic
Pulmonary over circulation
Shunts causing increase in right heart size
Qp:Qs > 1.5
When do shunts require treatment?
When they are symptomatic
Pulmonary over circulation
Shunts causing increase in right heart size
Qp:Qs > 1.5
What is the most common type of atrial septal defect?
Ostium Secundum
What are some common types of atrial septal defects?
Ostium Secundum
Patent Foramen Ovale
Ostium Primum
Sinus Venosus
Ostium Secundum
Most common ASD type
Formed by failed growth of the septum secundum OR rapid reabsorption of the septum primum
Mid atrial
What is the only type of ASD suitable for percutaneous closure?
Ostium Secundum ASD; defect in the middle of the atrial septum
Patent foramen Ovale (PFO)
Small channel that has little hemodynamic consequence; it is a remnant of the fetal foramen ovale
*In some cases PFO can be larger and require treatment
Patent foramen Ovale (PFO)
- Small channel that has little hemodynamic consequence; it is a remnant of the fetal foramen ovale
- Channel from birth; “Flap valve”
*In some cases PFO can be larger and require treatment
Why would a PFO normally close?
Closes due to pressure changes very early in life
Why would a PFO normally close?
Closes due to pressure changes very early in life
Closure of Fetal Shunts
- The initial inflation of the lungs causes changes:
- Decreases PVR results in increased BF from PA
- Increased BF from RA to RV and into the PA’s and less BF through the foramen ovale to the left atrium
- More blood returns from lungs increases pressure inLA
- Increased LA pressure and decreased RA pressure (due to pulmonary resistance) forces blood against septum primum causing hte formane ovale to close
What action functionally completes the separation of the heart into two pumps?
Closure of the PFO in a normal fetal heart after birth (changes in pulmonary pressures, resistance, BF)
Ostium Primum ASD Location
Low in the septum and can be considered a type of AV septal defect (AVSD)
Ostium Primum Sat Changes
Could have RA saturations lower than RV without a VSD
Ostium Secundum
Most common ASD type (90%)
Formed by failed growth of the septum secundum OR rapid reabsorption of the septum primum
Mid atrial
Ostium Primum Sat Changes
Could have RA saturations lower than RV without a VSD
Sinus Venosus ASD Location
high in the septum where the vena cava intersects with the right atrium; may be inferior or superior
What is sinus venosus ASD frequently associated with?
Partial anomalous venous return (PAPVR)
What is sinus venosus ASD frequently associated with?
Partial anomalous venous return (PAPVR)
What forms separate chambers of the heart?
Embryonic septation
What are key aspects in heart development?
- Embryonic/fetal circulation is different to the neonatal circulation
- Embryonic septation forms separate chambers
- Several septal defects of heart septation may only become apparent on this transition
Which septal defect occurs in us all?
The foramen ovale (between the 2 atria) which in general closes in the neonate over time
At what day does cardiac septation occur?
Day 27
How long does cardiac septation last?
10 days
When do the formation of cardiac septa occur?
Simultaneously
During cardiac septation, how does the external appearance change?
No major changes in external appearance
Atrial Septation at what days?
27-28 (for 10 days)
What happens during atrial septation?
- The paired atria fuse together to form a common atrium
- Atrial septation occur simultaneously and in cooperation with ventricular septation
- Atrial septation also lasts 10 days