Spontaneous Remission of Congenital Complete Atrioventricular Block in Anti-Ro/La Antibody-Negative Monozygotic Twins: Case Report

Congenital complete atrioventricular block (CAVB) is seen in approximately one in every 20.000 live births.Congenital CAVB is rarer in patients that are anti-Ro/La negative or who do not exhibit any structural heart disease.More than 90% of congenital atrioventricular blocks (AVB) are accompanied by maternal autoimmune antibodies or structural heart disease.The remaining 10% are idiopathic AVB (1).Congenital CAVB in monozygotic twins is rarer, and usually defined in the literature as an autoimmune mechanism (2,3).We present here a case of discordant CAVB that sustained remission in monozygotic twin infants who were autoimmune negative and did not have any structural heart disease.To the best of our knowledge, this is the first to report discordant CAVB regression as shown in monozygotic twins with no autoimmune evidence. CASE PRESENTATIONThe 26-year-old healthy mother had given birth in her first spontaneous, uneventful pregnancy to monozygotic twins at week 35, one of whom had a birth weight of 2.320 grams.The mother did not have a history of infection, metabolic disease, autoimmune disease, or drug usage during the pregnancy period.After the evaluation of the fetuses at 35 th week of gestation, an emergency cesarean section was performed on the diagnosis of fetal distress due to bradycardia of the index fetus which was determined by a non-stress test.Following birth, both babies had normal Apgar scores.While the first twin's physical examination proved her to be normal with a pulse rate consistent with her age, the second twin had a pulse rate of approximately 40 beats/ minute; therefore, the twin with bradycardia was hospitalized.