Hypoplastic Left Heart Syndrome: Karyotyping Is Key


RENO, NEV. — Fetuses with hypoplastic left heart syndrome and normal chromosomes are unlikely to die in utero, according to a retrospective study of 176 fetuses diagnosed prenatally with the disorder.

Of these fetuses, which were diagnosed over a 12-year period, 133 were live born, 32 underwent therapeutic abortion, and 3 died in utero. The outcome for eight of the fetuses is unknown, Rebecca H. Allen, M.D., and her associates wrote in a poster presentation at the annual meeting of the Society for Maternal-Fetal Medicine.

Of the 3 fetuses that died in utero, 1 had trisomy 13, 1 had trisomy 18, and 1 was not karyotyped. Both of the fetuses with abnormal karyotypes had other anomalies detected by ultrasound. The third had no anomalies, but was one of triplets. Only 2 of the 133 live-born fetuses had abnormal karyotypes; 29 had other anomalies.

Parents of fetuses with hypoplastic left heart syndrome are sometimes offered interventional procedures, and fetal death occasionally follows. It's unknown whether such procedures contribute to intrauterine death.

“This finding does not argue against prenatal cardiac interventional procedures,” Dr. Allen of Brigham and Women's Hospital, Boston, said in an interview, stating that the study was designed to examine the natural history of the syndrome.

The study emphasizes “the need for karyotype in the evaluation of a fetus with hypoplastic left heart syndrome. A fetus with normal chromosomes and an isolated hypoplastic left heart lesion is a potentially good candidate for in utero cardiac intervention,” she said.

This fetus has hypoplastic left heart syndrome. This sonogram shows a very small left ventricle (LV) and an enlarged right ventricle (RV). The right atrium (RA) and left atrium (LA) also are indicated. Courtesy Dr. Rebecca H. Allen

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