Characteristics and long-term outcome of non-immune isolated atrioventricular block diagnosed in utero or early childhood: a multicentre study

Aims The natural history of congenital or childhood non-immune, isolated atrioventricular (AV) block is poorly defined. Methods and results We retrospectively studied 141 children with isolated, non-immune AV block diagnosed in utero , or up to 15 years of age, at 13 French medical centres, between 1980 and 2009. Patients with structural heart disease or maternal antibodies were excluded. Atrioventricular block was asymptomatic in 119 (84.4%) and complete in 100 (70.9%) patients. There was progression to complete AV block in 29/41 (70.7%) patients with incomplete AV block over 2.8 ± 3.4 years (1–155 months), but all patients with incomplete AV block may not have been included in the study. Narrow QRS complex was present in 18 of 26 patients (69.2%) with congenital, and 106 of 115 (92.2%) with childhood AV block. Pacemakers were implanted in 112 children (79.4%), during the first year of life in 18 (16.1%) and before 10 years of age in 90 (80.4%). The mean interval between diagnosis of AV block and pacemaker implants was 2.6 ± 3.9 years (0–300 months). The pacing indication was prophylactic in 70 children (62.5%). During a mean follow-up of 11.6 ± 6.7 years (1–32 years), no patient died or developed dilated cardiomyopathy (DCM). The long-term follow-up was uncomplicated in 127 children (90.1%). Conclusion In this large multicentre study, the long-term outcome of congenital or childhood non-immune, isolated AV block was favourable, regardless of the patient's age at the time of diagnosis. No patient died or developed DCM, and pacemaker-related complications were few.