Background: The purpose of this study was to evaluate the clinical outcome of fetuses with bradyarrhythmias or complete heart block (CHB) in the setting of fetal structural heart disease (CHD) or of maternal collagenosis with and without treatment.
Methods: A retrospective analysis of echocardiographic studies performed in 14 fetuses (mean gestational age 25.5, range 19 - 36 weeks) referred for exclusion or diagnosis of bradyarrhytmias was performed. Maternal SS-A/Ro and SS-B/La antibodies were measured by ELISA.
Results: 14 fetuses showed bradyarrhythmias or complete heart block in combination with severe cardiac malformations (n = 7) or with positive maternal antibodies (n = 7). Only one of the fetuses with CHD survived infancy as opposed to 5/7 fetuses with complete atrioventricular block in the setting of maternal collagenosis. Maternal treatment with corticosteroids did not seem to influence the rhythm disorder.
Conclusion: Fetal echography is a safe method to detect bradyarrhythmias or complete atrioventricular block. When associated with structural heart defects, fetal prognosis is poorer than in combination with maternal collagenosis.