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Common Congenital Heart Lesions - page 2 / 126

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  • Fetal Circulation:

Umbilical Vein Æ ductus venosus Æ IVC OR Umbilical Vein Æ portal vein Æ liver Æ hepatic veins Æ IVC

From IVC (high O2) Æ RA Æ foramen ovale Æ LA Æ LV

From LV:

  • 1.

    carotid and subclavian to brain (60%)

  • 2.

    descending aorta (30%)

  • 3.

    coronary arteries (10%)

OR

From IVC (high O2)Æ RA Æ RV* Æ PA Æ ductus arteriosus** Æ descending aorta

OR

Æ PA Æ lungs

*During fetal life, RV accounts of 2/3 of CO

**Most blood goes through the shunt because of increased pulmonary vascular resistance (because lungs filled with fluid)

  • At birth

    • o

      Ductus venosis constricts when umbilical cord clamped

      • o

        Foramen ovale closes due to increased LA pressure and decreased RA pressure

      • o

        Ductus arteriosus constricts after birth because of decreased prostaglandin E1 levels

Congenital Heart Lesions: well tolerated before birth due to shunting

  • 1.

    Cyanotic:

    • a.

      right to left shunting in the heart

    • b.

      ASD, VSD, PDA, AS, PS, Coarctation

    • c.

      ASD, VSD, and PDA cause VOLUME overload

    • d.

      AS, PS, and Coarctation cause PRESSURE overload

  • 2.

    Acyanotic: left to right shunt, associated with Eisenmenger syndrome

    • a.

      Eisenmenger syndrome: large left to right shunt Æ increased volume and pressure in LA Æ hypertrophy of pulmonary arterioles Æ increased pulmonary vascular resistance Æ increased pressure on right side of heart Æ SHUNT REVERSAL (RIGHTÆ LEFT) Æ hypoxemia and cyanosis

    • b.

      Tetralogy of Fallot, TGA, Eisenmenger’s

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