Congenital heart disease

Left-to-Right Shunt

  • Atrial Septal Defect
    • Commonest clinically
    • Atrial septum: septum primum + septum secondum, both have a hole but in opposite direction called foramen ovale to allow blood to pass through during pregnancy
    • Closes when R pressure drops and Left increases, smaller ASDs usually don’t have symptoms until adulthood
    • Development of septum secondum is the commonest
    • Pt presents with heart failure, R-L shunt
    • Reversal of shunt leads to R-L shunt, cyanosis, paradoxical embolizations etc Eisenmenger’s complex
  • Ventral Septal Defect
    • common at time of birth but 50% close without treatment
    • 2nd commonest overall, after ASD
    • Small ones are asymptomatic or produce a mild murmur
    • RVH results in R-L shunt
  • Patent Ductus Arteriosis
    • Normal DA remains patent following birth
    • Harsh murmurs, only large PDA produce pulmonary HTN

Right-to-Left Shunt

Produce cyanosis and clubbing

  • Tetralogy of Fallot
    • Defective septum development:
      • VSD
      • RVH
      • Pulmonary Stenosis
      • Overriding aorta (to the right side) => aorta gets blood from both sides
    • Mild: like VSD, no cyanosis
    • R to L shunt => predisposes to infections
    • Associated PDA or ASD can shunt more O2
  • Transposition of the Great Arteries
    • Altered great vessels
    • Survival only possible with associated VSD
    • Cyanosis, RHF
    • Death in first month if not surgically corrected


  • Coarctation of the Aorta
    • More common in females, but females with Turner’s have high incidence
    • Infantile-preductal: coarctation proximal to PDA, hence R-L shunt
    • Adult: coarctation distal to PDA, hence PDA closes but => upper extremity HTN, lower extremity claudication



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