Persistent Fetal Sinus Bradycardia Associated with Maternal Anti-SSA/Ro and Anti-SSB/La Antibodies

Objective.To study the clinical course and outcome of fetal sinus bradycardia (SB) due to maternal antibody-induced sinus node dysfunction.Methods.We reviewed the maternal, prenatal, and postnatal findings of fetuses with SB associated with elevated maternal anti-SSA/Ro and anti-SSB/La antibodies.Results.Of the 6 cases diagnosed prenatally, 3 had isolated SB persisting after birth and had a good prognosis. Three fetuses with SB and severe myocardial involvement (congenital complete heart block and/or endocardial fibroelastosis) succumbed in utero in spite of treatment. Postmortem histopathology in 1 fetus showed inflammatory destruction of the sinus and atrioventricular nodes. SB was detected incidentally in a 7-year-old girl. She had intermittent heart block with progressive sinus arrest requiring permanent pacemaker.Conclusion.Fetal SB associated with maternal autoantibodies may persist in childhood, with a good prognosis in the absence of widespread cardiac involvement.