Congenital Cardiac LesionsCongenital Cardiac Lesions

OverviewOverview

Three Shunts of Fetal CirculationThree Shunts of Fetal Circulation

Ductus ArteriosusDuctus Arteriosus Protects lungs against circulatory overloadProtects lungs against circulatory overload Allows RV to strengthenAllows RV to strengthen High pulmonary vascular resistance, low pulmonary High pulmonary vascular resistance, low pulmonary

blood flowblood flow Carries moderately saturated bloodCarries moderately saturated blood

Ductus VenosusDuctus Venosus Connects umbilical vein to IVCConnects umbilical vein to IVC Flow regulated via sphincterFlow regulated via sphincter Conducts highly oxygenated bloodConducts highly oxygenated blood

Foramen OvaleForamen Ovale Shunts highly oxygenated blood from RA to LAShunts highly oxygenated blood from RA to LA

Circulatory Changes at BirthCirculatory Changes at Birth

Aeration of Lungs at BirthAeration of Lungs at BirthDecreased pulmonary vascular resistance Decreased pulmonary vascular resistance

secondary to lung expansionsecondary to lung expansion Increase in pulmonary blood flow- raising LA Increase in pulmonary blood flow- raising LA

pressure to higher than that of the IVCpressure to higher than that of the IVCThinning of walls of PA secondary to stretch Thinning of walls of PA secondary to stretch

as lungs increase in size with first few breathsas lungs increase in size with first few breaths

Changes Associated with Changes Associated with First Breath First Breath

Alveoli openAlveoli openPressure in pulmonary tissues decreasePressure in pulmonary tissues decreasePressure in R. heart decreasesPressure in R. heart decreasesPressure in the L. heart increases as Pressure in the L. heart increases as

blood returns from highly vascularized blood returns from highly vascularized pulmonary tissue to the LApulmonary tissue to the LA

Fate of the shunts…Fate of the shunts… Foramen Ovale: Foramen Ovale:

Closes at birth due to decreased flow from placenta and IVC Closes at birth due to decreased flow from placenta and IVC Pulmonary venous return causes pressure in LA to be higher Pulmonary venous return causes pressure in LA to be higher

than that in RAthan that in RA Ductus Arteriosus:Ductus Arteriosus:

Due to decreased pulmonary vascular resistance, PA pressure Due to decreased pulmonary vascular resistance, PA pressure falls below systemic pressure and blood flow through DA is falls below systemic pressure and blood flow through DA is diminisheddiminished

Closure mediated by bradykininClosure mediated by bradykinin Prostaglandin E2 may reopen DA Prostaglandin E2 may reopen DA

Umbilical VesselsUmbilical Vessels Constrict at birth and are then tied and cutConstrict at birth and are then tied and cut

The Normal HeartThe Normal Heart

Right-Sided Heart LesionsRight-Sided Heart Lesions

Other right-sided cardiac abnormalities that Other right-sided cardiac abnormalities that may present with or without cyanosis include:may present with or without cyanosis include:Pulmonary Valve and Infundibular StenosisPulmonary Valve and Infundibular StenosisPulmonary RegurgitationPulmonary RegurgitationAbsence of the pulmonary valveAbsence of the pulmonary valvePulmonary Artery StenosisPulmonary Artery StenosisTricuspid StenosisTricuspid StenosisDouble-chambered right ventricleDouble-chambered right ventricleEbstiens anomalyEbstiens anomaly

Ebsteins AnomalyEbsteins Anomaly Defect that mainly affects the tricuspid valve. Defect that mainly affects the tricuspid valve.

The tricuspid valve is located lower than normalThe tricuspid valve is located lower than normal The upper part of the right ventricle is part of the right atrium, The upper part of the right ventricle is part of the right atrium,

making the right ventricle is too small and the right atrium is too making the right ventricle is too small and the right atrium is too large. large.

Tricuspid valve may be malformed. Tricuspid valve may be malformed. Abnormal leaflets may let blood leak back into the atrium after it Abnormal leaflets may let blood leak back into the atrium after it

has flowed into the ventricle. The backward flow of blood makes has flowed into the ventricle. The backward flow of blood makes the atrium even larger and the ventricle even smaller. the atrium even larger and the ventricle even smaller.

Often Associated with other heart lesionsOften Associated with other heart lesions ASDASD Pulmonary StenosisPulmonary Stenosis Pulmonary AtresiaPulmonary Atresia

TreatmentTreatment The mainstays of treatment for cyanotic heart The mainstays of treatment for cyanotic heart

lesions are oxygen and prostaglandin.lesions are oxygen and prostaglandin. PGEPGE1 1 serves to reopen the ductus arteriosus or serves to reopen the ductus arteriosus or

prevent it from closing, which allows partially prevent it from closing, which allows partially desaturated blood to enter PA and be desaturated blood to enter PA and be oxygenated.oxygenated.

Initial dose of PGEInitial dose of PGE1 1 is 0.1 mg/kg/min; can be is 0.1 mg/kg/min; can be reduced to 0.02-0.05 mg/kg/min when patient is reduced to 0.02-0.05 mg/kg/min when patient is stable.stable.

Adverse Effects of PGEAdverse Effects of PGE1 1 are rare, including are rare, including apnea, hypotension, edema, and fever.apnea, hypotension, edema, and fever.

Treatment- continuedTreatment- continued

General procedure for cyanotic heart General procedure for cyanotic heart lesions involves a systemic to PA shunt.lesions involves a systemic to PA shunt.

Procedure known as the Blalock-Taussig Procedure known as the Blalock-Taussig shunt.shunt.Uses a small Gore-TexUses a small Gore-Tex® shunt to connect ® shunt to connect

either left or right subclavian to left or right either left or right subclavian to left or right branch PA.branch PA.

Allows partially desaturated blood to enter PA, Allows partially desaturated blood to enter PA, increasing pulmonary blood flow and increasing pulmonary blood flow and oxygenationoxygenation