Late development of complete atrioventricular block may be immune mediated and congenital in origin

Aim To investigate the correlation between maternal autoantibodies and age at diagnosis of isolated complete atrioventricular (AV) block (CAVB) and to study signs of late progression of foetal immune‐mediated insults in cases of postnatally diagnosed CAVB. Methods Patients with CAVB (n = 190) identified in a population‐based manner were included. Maternal autoantibody profile was correlated with age at CAVB diagnosis. A structured review of medical records was performed if a late CAVB diagnosis (>27 days post‐partum) was associated with a sero‐positive mother. Results Maternal Ro/La autoantibodies were observed in 88% of cases with a congenital diagnosis. Thirteen cases with a sero‐positive mother and late CAVB diagnosis were found (age‐range: 4 months–43 years). In two cases, CAVB was diagnosed in conjunction with infections, one case had a family history of cardiomyopathy and two cases had nontypical clinical presentations, indicating alternative pathogenetic mechanisms. In the remaining eight cases, no likely factors inducing CAVB, other than maternal autoantibodies, could be identified. Conclusion Our observations support the hypothesis that late progression to CAVB can be the result of an immune‐mediated pathogenetic mechanism during foetal life. An autoantibody‐associated diagnosis after the neonatal period is therefore possible, and testing of maternal serology at the time of diagnosis is recommended.