DEVELOPMENT OF SIGNIFICANT LEFT AND RIGHT-VENTRICULAR HYPOPLASIA IN THE 2ND AND 3RD TRIMESTER FETUS

Although most forms of fetal heart disease are present by the end of t he first trimester, after embryogenesis is complete, some lesions may evolve late in gestation, resulting in more severe disease at birth. C oarctation of the aorta can be associated with progression in the seve rity of distal arch hypoplasia.(1) Development or progression in sever ity of pulmonary artery hypoplasia can occur in tetralogy of Fallot.(2 ) Right ventricular outflow tract obstruction can develop or worsen as an isolated lesion(3) or in the presence of a dysplastic or Ebstein-L ike tricuspid valve with tricuspid regurgitation,(4) tetralogy of Fall ot,2 or more complex cardiac lesions.(5) The early prenatal appearance of the fetal heart may not always represent the final extent of the l esion in the neonate.(6) We have recently encountered two cases in whi ch serial prenatal and postnatal study revealed development of signifi cant left (one case) and right (one case) ventricular hypoplasia throu gh the second half of gestation in fetuses with severe aortic stenosis or pulmonary stenosis, respectively, and intact ventricular septum.