Shunts and Obstructions Flashcards
Segmental approach to CHD
Look at segements and their connections
Great veins –> veno-atrial –> atria –> atrial-ventricular –> ventricles –> ventriculo-arterial –> great arteries
Most common ASD?
Septum secundum
What chambers are the first to dilate in
- ASD shunt
- VSD shunt
- RA and RV
2. LA and LV
Acyanotic shunts
Left to right! ASD VSD AVSD PSA
Cyanotic shunts
Right to left!
Eisenmenger syndrome (VSD, AVSD, PDA)
Tetralogy of Fallot
Mixed shunt
Cyanotic!
Transposition of the great arteries
Degree/direction of shunting depends on which 3 things?
Pressure difference between chambers
Relative compliance between chambers
Size of defect
What are some of the sequelae from a left to right shunt?
Pulmonary over circulation Pulmonary hypertension (stiffening of PAs) Left sided chamber dilation Left sided chamber dysfunction Clinical heart failure Arrhythmias
How does the normal O2 sat change in a VSD? In which places?
In RV and PA the sat increased from 73% to 79% because you are recirculating oxygenated blood
What are some sequelae from a PDA?
Same as VSD Pulmonary over circulation Pulmonary hypertension (stiffening of PAs) Left sided chamber dilation Left sided chamber dysfunction Clinical heart failure Arrhythmias
How does the normal O2 sat change in a PDA? In which places?
In the pulmonary artery, the sat increases from 73% to 85%
Eisenmenger syndrome
When you have left to right shunting that is not detected you get pulmonary over circulation, pulmonary hypertension, becomes severe, and then the pulmonary pressures exceed systemic pressures
When this happens, the shunt reverses from right to left
Become cyanotic
The difference between right and left shunting in Eisenmenger vis ToF?
In E, the right to left is because of pulmonary hypertension
In ToF the R to L is because of the obstruction to RV outflow tract - fix this and you’ll be fine because pulmonary circulation is fine
How does the normal O2 sat change in ToF? In which places?
RV: decreases from 73 to 69%
LV and Aorta: decrease from 98 to 85%
3 ways to survive transposition
VSD, ASD, PDA
This forms a R to L shunt, but at least you get some mixing
Where can anatomic obstruction occur?
Supra valvular
Valvular
Sub valvular
Implications of an obstruction
No shunts, so oxygenation is normal
But if obstruction is severe, could lead to systemic hypoperfusion which would then result in increased oxygen extraction in the periphery, and low RH oxygen saturations
Major issue is of the pressure gradients across the obstruction, and the effects this has on the chambers
Aortic coarctation sequelae
Narrowing/stenosis of the aorta leads to... Hypertension Increased LV pressure Distal hypoperfusion Progressive LV dilation and dysfunction Clinical heart failure
What clinical findings would you do for coarctations
Measure BP in arms (high)
Measure BP in legs (10-15 mmHg lower)
