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Congenital Heart Defects
Functional Overview
Dr. Yasser Salem
Objectives
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Obstructive lesions right or left
Mixing lesions
Shunt lesions
left to right or right to left
Univentricular physiology
Miscellaneous
– Anomalies of coronary arteries
– Vascular ring
Obstructive cardiac lesions
Cyanotic
Acyanotic
Obstructive cardiac lesions
• low OXYGEN
Enough blood, just not enough oxygen in the blood
COMPLEX CARDIAC LESIONS = MIXING LESIONS
• low BLOOD
Enough oxygen, just not enough blood flow
OBSTRUCTIVE CARDIAC LESIONS
• COMBINATION
Left sided obstructive lesions
Left sided obstructive lesions
Increased flow
Backward effects
Pulmonary venous congestion
Increase RV afterload
RV hypertrophy and failure
Systemic venous congestion
Forward effects
Decrease peripheral tissue perfusion
Decrease coronary perfusion
Myocardial ischemia
Left sided obstructive lesion
• Aortic stenosis
– Subvalvular (SAM, Pompe)
– Valvular congenital stenosis
– Supravalvular (Aortic coarc., hypoplastic arch)
• Mitral stenosis
– Subvalvular (Shone’s)
– Valvular congenital stenosis
– Supravalvular (core triatriatum)
Shone’s anomaly
Core triatriatum
Left sided obstructive lesion
• Hypoplastic left heart syndrome (HLHS)
• Tricuspid atresia with transposed great
arteries
• Double-inlet left ventricle
• IAA
• DORV (some variations)
Right sided obstructive lesions
Right sided obstructive lesions
Backward effects
Pulmonary venous congestion
Increase RV afterload
RV hypertrophy and failure
Systemic venous congestion
Forward effects
Decrease peripheral tissue perfusion
Decrease coronary perfusion
Myocardial ischemia
Decrease pulmonary perfusion (lung oligemia)
CYANOSIS
Right sided obstructive lesions
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Tricuspid atresia
Pulmonary atresia with IVS
TOF with pulmonary atresia
Severe Ebstein’s anomaly of the tricuspid
valve
• Critical PS
• DORV (some variations)
Right
Left sided obstructive lesion
• Aortic
stenosis
Pulmonary
stenosis
–Subvalvular (SAM, Pompe)
–Valvular congenital stenosis
–Supravalvular (Aortic coarc., hypoplastic arch)
Tricuspid
stenosis
• Mitral
stenosis
–Subvalvular (Shone’s)
–Valvular congenital stenosis
–Supravalvular (core triatriatum)
Right sided obstructive lesion
• Pulmonary stenosis
– Subvalvular (Fallot’s tetralogy)
– Valvular congenital stenosis or atresia
– Supravalvular (hypoplastic pulmonary arteries)
• Tricuspid stenosis
– Subvalvular (DCRV, Ebestien)
– Valvular congenital stenosis
– Supravalvular (eustachian valve)
Eustachian valve
Double Chamber Right Ventricle
(DCRV)
Mixing lesions
• Defects with mixing of oxygenated and
deoxygenated blood
• Partial desaturation lead to compensatory
in red cell mass and increase 2,3 DPG
with increase in blood viscosity.
Left sided obstructive lesions
• Hypoplastic left heart syndrome (HLHS)
• Tricuspid atresia with transposed great
arteries
• Double-inlet left ventricle
• IAA
• DORV (some variations)
Left sided obstructive lesions
• Complete mixing of systemic and pulmonary
venous return
• Ventricular outflow directed primarily to the PA
• Systemic blood flow (Qs)
– Largely by right-to-left ductal shunting
– Dependent on the relative PVR and SVR
• Systemic outflow obstruction is poorly tolerated
• Usually accompanied by signs or symptoms of
shock
Left sided obstructive lesions
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Maintain preload at maximum
Maintain afterload at maximum
Maintain contractility in neonates at maximum
Maintain below maximum contractility in older patients
Relative bradycardia is preferred not in neonates
Quick guide to pediatric cardiopulmonary care, edwards
Right sided obstructive lesions
Right sided obstructive lesions
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•
•
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Tricuspid atresia
Pulmonary atresia with IVS
TOF with pulmonary atresia
Severe Ebstein’s anomaly of the tricuspid
valve
• Critical PS
• DORV (some variations)
Right sided obstructive lesions
• Complete mixing of systemic and pulmonary
venous return
• Ventricular outflow predominantly directed out
the aorta
• Low pulmonary blood flow (Qp) in singleventricle patients implies an obligate right-to-left
shunt (generally atrial level)
• Clinical consequences of low Qp are variable
Mixing lesions
• Qp/Qs dependent upon PVR SVR
balance
• Hypoxemia and its consequences
Adjust PVR
SVR balance to
gain optimal
oxygen delivery
Obstructive lesions
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Qs decreased
Low CO
Hypotension
Coronary perfusion
decreased
• LV failure
Qp decreased
Hypoxemia
RV hypertrophy
RV dysfunction
TR
• Avoid increase
PVR
• Hyperoxia
• Hypoventilation
Avoid SVR decrease
Maintain preload
Maintain PDA patency
• Avoid decrease
PVR
• Relative hypoxia
• Relative
hypercarbia
Objectives
•
•
•
•
•
Obstructive lesions right or left
Mixing lesions
Shunt lesions
left to right or right to left
Univentricular physiology
Miscellaneous
– Anomalies of coronary arteries
– Vascular ring
Shunt lesions
• Shunts may intracardiac or extracardiac
• Large shunts are non restrictive with low
pressure gradient across
• Small shunts are restrictive with high
pressure gradient across
Left to right shunt
Factors affecting shunt flow
Ventricular
or
Great artery level
Atrial level
Relative
compliance
Size of
defect
Right vs Left
ventricle
Pressure gradient
between
chambers or arteries
Ratio of
Blood
viscosity
PVR to SVR
Left to right shunt
Pathology of shunt flow
Atrial or
ventricular
shunts
Great artery
shunts
All shunts
↑RV filling
↑Pulmonary blood flow
↑RVEDV and
↑RVEDP
Pulmonary edema
RV failure
↑LA and LV blood flow
↓Diastolic BP
↑LVEDV and ↑LVEDP
↓Coronary
perfusion
pressure
LV failure
Myocardial
ischemia
↑PVR
Pulmonary hypertension
Shunt reversal
RV hypertrophy
Pressure RV > LV
Eisenmenger’s
syndrome
Left to right shunt
Pathology of shunt flow
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Avoid decrease
increase ininpulmonary
PVR
flow
Enhance
Avoid decrease
the useinofsystemic
vasoconstrictors
flow
Avoid extensive diastolic hypotension
Avoid increase in total blood volume
Pulmonary artery banding
Pulmonary artery banding
• Good banding
– High pressure gradient across band by echo
– Non-congested lung fields
Objectives
•
•
•
•
•
Obstructive lesions right or left
Mixing lesions
Shunt lesions
left to right or right to left
Univentricular physiology
Miscellaneous
– TGA
– Anomalies of coronary arteries
– Vascular ring
Transposition of great arteries
• Mixing is mandatory for life
• Left ventricle mass and
function
• Coronary anatomy
Coronary Anomalies
ALCAPA
Vascular ring
Vascular ring
A
I
R
Determinants of cardiac output
preload
Afterload
Heart
rate
CNTRACTILITY
CARDIAC OUTPUT
OXYGEN DELIVERY
Arterial O2 content
OXYGEN extraction
Venous saturation
Angels
Demons
• Septal aneurysm
• Atralization of the RV
• Persistent left SVC
• Parachute mitral valve
• Interrupted IVC
• Interrupted aortic arch
• Restrictive VSD
• Non-restrictive VSD
• High pressure gradient
across VSD
• Law pressure gradient
across VSD
• Law pressure gradient
across left or right
obstructive lesions
• High pressure gradient
across left or right
obstructive lesions