Outcome in young patients with isolated complete atrioventricular block and permanent pacemaker treatment: A nationwide study of 127 patients

Background Subgroups of pacemaker (PM)–treated children with isolated complete atrioventricular block are at risk of developing left ventricular (LV) dysfunction. Objectives We aimed to compare the long-term outcome in anti-SSA-Ro/SSB-La antibody-exposed (AB+) and unexposed (AB−) patients and identify preimplantation variables associated with poor outcome. Methods In total, 127 PM-treated patients aged 0–17 years with isolated complete atrioventricular block were studied retrospectively. Results Sixty-three patients were diagnosed prenatally, of whom 92% were AB+. Before PM treatment, fractional shortening (FS) z-score was significantly lower in AB+ patients than in AB− patients (−0.14 ± 3.6 vs 2.03 ± 2.3). Before PM implantation, there were sex differences (male/female) in median time from diagnosis to PM implantation (0.2 years vs 1.0 years), median neonatal heart rate (50 beats/min vs 60 beats/min), left ventricular end-diastolic dimension (LVEDD) z-score (2.68 ± 1.41 vs 1.74 ± 1.40), and FS (−0.19 ± 3.38 vs 1.42 ± 2.98). The median age at PM implantation was 3.2 years, and median follow-up was 8.7 years. At follow-up, LVEDD and FS did not differ significantly between AB+ and AB− patients, but LVEDD was higher in patients diagnosed before 1 month of age. Nine patients (8%) developed LV dysfunction, and 4 died. LV dysfunction was associated with diagnosis before 1 month of age and abnormal LV function before PM implantation. Conclusion LV dysfunction at follow-up was seen only in cases diagnosed before 1 month, with abnormal echocardiography before PM implantation. Boys had a more compromised cardiac status and were paced at an earlier age than girls. Fetal AB exposure and male sex were related to abnormal LV function before PM therapy, but not at follow-up.