1. Congenital Cardiac Lesions

2. Overview

3. Three Shunts of Fetal Circulation Ductus Arteriosus Ductus Arteriosus Protects lungs against circulatory overload Protects lungs against circulatory overload Allows RV to strengthen Allows RV to strengthen High pulmonary vascular resistance, low pulmonary blood flow High pulmonary vascular resistance, low pulmonary blood flow Carries moderately saturated blood Carries moderately saturated blood Ductus Venosus Ductus Venosus Connects umbilical vein to IVC Connects umbilical vein to IVC Flow regulated via sphincter Flow regulated via sphincter Conducts highly oxygenated blood Conducts highly oxygenated blood Foramen Ovale Foramen Ovale Shunts highly oxygenated blood from RA to LA Shunts highly oxygenated blood from RA to LA

4. Circulatory Changes at Birth Aeration of Lungs at Birth Aeration of Lungs at Birth Decreased pulmonary vascular resistance secondary to lung expansion Decreased pulmonary vascular resistance secondary to lung expansion Increase in pulmonary blood flow- raising LA pressure to higher than that of the IVC Increase in pulmonary blood flow- raising LA pressure to higher than that of the IVC Thinning of walls of PA secondary to stretch as lungs increase in size with first few breaths Thinning of walls of PA secondary to stretch as lungs increase in size with first few breaths

5. Changes Associated with First Breath Alveoli open Alveoli open Pressure in pulmonary tissues decrease Pressure in pulmonary tissues decrease Pressure in R. heart decreases Pressure in R. heart decreases Pressure in the L. heart increases as blood returns from highly vascularized pulmonary tissue to the LA Pressure in the L. heart increases as blood returns from highly vascularized pulmonary tissue to the LA

6. 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 than that in RA Pulmonary venous return causes pressure in LA to be higher than that in RA Ductus Arteriosus: Ductus Arteriosus: Due to decreased pulmonary vascular resistance, PA pressure falls below systemic pressure and blood flow through DA is diminished Due to decreased pulmonary vascular resistance, PA pressure falls below systemic pressure and blood flow through DA is diminished Closure mediated by bradykinin Closure mediated by bradykinin Prostaglandin E2 may reopen DA Prostaglandin E2 may reopen DA Umbilical Vessels Umbilical Vessels Constrict at birth and are then tied and cut Constrict at birth and are then tied and cut

7. The Normal Heart

8. Right-Sided Heart Lesions Other right-sided cardiac abnormalities that may present with or without cyanosis include: Other right-sided cardiac abnormalities that may present with or without cyanosis include: Pulmonary Valve and Infundibular Stenosis Pulmonary Valve and Infundibular Stenosis Pulmonary Regurgitation Pulmonary Regurgitation Absence of the pulmonary valve Absence of the pulmonary valve Pulmonary Artery Stenosis Pulmonary Artery Stenosis Tricuspid Stenosis Tricuspid Stenosis Double-chambered right ventricle Double-chambered right ventricle Ebstiens anomaly Ebstiens anomaly

9. Ebsteins Anomaly Defect that mainly affects the tricuspid valve. Defect that mainly affects the tricuspid valve. The tricuspid valve is located lower than normal The tricuspid valve is located lower than normal 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 large. 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 large. Tricuspid valve may be malformed. Tricuspid valve may be malformed. Abnormal leaflets may let blood leak back into the atrium after it has flowed into the ventricle. The backward flow of blood makes the atrium even larger and the ventricle even smaller. Abnormal leaflets may let blood leak back into the atrium after it has flowed into the ventricle. The backward flow of blood makes the atrium even larger and the ventricle even smaller. Often Associated with other heart lesions Often Associated with other heart lesions ASD ASD Pulmonary Stenosis Pulmonary Stenosis Pulmonary Atresia Pulmonary Atresia

10. Treatment The mainstays of treatment for cyanotic heart lesions are oxygen and prostaglandin. The mainstays of treatment for cyanotic heart lesions are oxygen and prostaglandin. PGE 1 serves to reopen the ductus arteriosus or prevent it from closing, which allows partially desaturated blood to enter PA and be oxygenated. PGE 1 serves to reopen the ductus arteriosus or prevent it from closing, which allows partially desaturated blood to enter PA and be oxygenated. Initial dose of PGE 1 is 0.1 mg/kg/min; can be reduced to 0.02-0.05 mg/kg/min when patient is stable. Initial dose of PGE 1 is 0.1 mg/kg/min; can be reduced to 0.02-0.05 mg/kg/min when patient is stable. Adverse Effects of PGE 1 are rare, including apnea, hypotension, edema, and fever. Adverse Effects of PGE 1 are rare, including apnea, hypotension, edema, and fever.

11. Treatment- continued General procedure for cyanotic heart lesions involves a systemic to PA shunt. General procedure for cyanotic heart lesions involves a systemic to PA shunt. Procedure known as the Blalock-Taussig shunt. Procedure known as the Blalock-Taussig shunt. Uses a small Gore-Tex® shunt to connect either left or right subclavian to left or right branch PA. Uses a small Gore-Tex® shunt to connect either left or right subclavian to left or right branch PA. Allows partially desaturated blood to enter PA, increasing pulmonary blood flow and oxygenation Allows partially desaturated blood to enter PA, increasing pulmonary blood flow and oxygenation