Congenital Heart DefectsFunctional Overview

Dr. Yasser Salem

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

Cyanotic Acyanotic

Obstructive cardiac lesions

Obstructive cardiac lesions

• low OXYGENEnough 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

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

Increased flow

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

• Hypoplastic left heart syndrome (HLHS)

• Tricuspid atresia with transposed great arteries

• Double-inlet left ventricle

• IAA

• DORV (some variations)

Left sided obstructive lesion

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

• 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

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)

LeftRight

•Pulmonary stenosis

•Tricuspid stenosis

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.

• 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

Left sided obstructive lesions

• 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

• 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 single-ventricle patients implies an obligate right-to-left shunt (generally atrial level)

• Clinical consequences of low Qp are variable

Right sided obstructive lesions

Mixing lesions

• Qp/Qs dependent upon PVR SVR balance

• Hypoxemia and its consequences

Adjust PVR SVR balance to gain optimal

oxygen delivery

• Qp decreased• Hypoxemia• RV hypertrophy• RV dysfunction• TR

Obstructive lesions

• Qs decreased• Low CO• Hypotension• Coronary perfusion

decreased• LV failure

Avoid SVR decreaseMaintain preloadMaintain PDA patency • Avoid decrease PVR

• Relative hypoxia• Relative hypercarbia

• Avoid increase PVR• Hyperoxia• Hypoventilation

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 shuntFactors affecting shunt flow

Atrial levelVentricular

or Great artery level

Relative compliance

Right vs Left ventricle

Blood viscosity

Size of defect

Pressure gradient between

chambers or arteries

Ratio of

PVR to SVR

Left to right shuntPathology of shunt flow

↑RV filling

↑RVEDV and ↑RVEDP

RV failure

↑Pulmonary blood flow

Pulmonary edema

↑PVR

Pulmonary hypertension

RV hypertrophy

↑LA and LV blood flow

↑LVEDV and ↑LVEDP

LV failure

↓Diastolic BP

↓Coronaryperfusion pressure

Myocardial ischemia

Pressure RV > LV

Shunt reversal

Eisenmenger’s syndrome

Atrial or ventricular

shunts

Great artery shunts

All shunts

Left to right shuntPathology of shunt flow

• Avoid increase in pulmonary flow

• Avoid decrease in systemic flow

• Avoid extensive diastolic hypotension

• Avoid increase in total blood volume

• Avoid decrease in PVR

• Enhance the use of vasoconstrictors

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

AIR

Determinants of cardiac output

CNTRACTILITY CARDIAC OUTPUT

OXYGEN DELIVERY

Afterload

Heart rate

OXYGEN extraction Venous saturation

Arterial O2 content

preload

Angels

Demons

• Septal aneurysm

• Persistent left SVC

• Interrupted IVC

• Restrictive VSD

• High pressure gradient across VSD

• Law pressure gradient across left or right obstructive lesions

• Atralization of the RV

• Parachute mitral valve

• Interrupted aortic arch

• Non-restrictive VSD

• Law pressure gradient across VSD

• High pressure gradient across left or right obstructive lesions