Fetal cor triatriatum dexter: a report of two cases associated with nuchal edema in early second trimester.

Two early-2nd-trimester fetuses were aborted as a result of nuchal edema and suspected severe heart malformation. At autopsy one fetus demonstrated nuchal edema, mild hydronephrosis, and cor triatriatum dexter associated with ventricular septal defect and tubular hypoplasia of the aortic arch. The other fetus demonstrated severe nuchal edema, and cor triatriatum dexter was the only malformation. Cor triatriatum dexter is a rare cardiac malformation characterized by division of the right atrium into 2 compartments by a usually fenestrated membrane representing remnants of the right valve of the embryonic sinus venosus. This malformation has been diagnosed in adults and children by echocardiography, surgery, or autopsy but has not previously been published in fetuses.