Pathology
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Fetopathology and developmental pathology of the embryo and fetus
Marta Ježová, Josef Feit et al.
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Pulmonary atresia with intact ventricular septum
Macroscopic appearance
  • pulmonary atresia is usually valvular in origin
  • the infundibulum may be stenotic or atretic as well
  • no defect in the ventricular septum
  • the tricuspid valve is rarely normal
  • two types are desribed according to the size of the right ventricle:
    • type 1 with small ventricle: tricuspid annulus is hypoplastic, the right ventricle has thick walls with a slit like cavity and thickened endocardium. Intramyocardial sinusoids are seen in approximately 50% of type I. The hypoplastic right ventricle feeds into the intramyocardial sinusoids which communicate with with torturous coronary arteries, coronary veins and sinus coronarius draining ultimately into the right atrium.
    • type 2 with normal or large right ventricle: the tricuspid valve is always insufficient. The tricupid leaflets are dysplastic, fused or present frank Ebstein malformation. The right ventricle is of normal size or enlarged, the right atrium is massively dilated. Intramyocardial sinusoids are not found.
Clinical signs
  • pulmonary blood flow is ductus dependent, the infants are severely cyanosed