Left atrial isomerism associated with asplenia: prenatal echocardiographic detection of complex congenital cardiac malformations.

Complex congenital heart disease with suspected isomerism of the atria was diagnosed in two fetuses of 20 and 29 weeks' gestation using two-dimensional and M-mode scanning techniques. The first pregnancy was terminated at 21 weeks' gestation and stillbirth occurred at 31 weeks' gestation in the second pregnancy. At postmortem examination, a thoracoabdominal discordancy was found; the spleen was absent and the arrangement of the abdominal vessels was as anticipated for asplenia, but the thoracic situs revealed a bilateral right-sided arrangement with left isomerism of the atria. The heart, otherwise, showed complex abnormalities as anticipated for asplenia.