NATURAL HISTORY OF NON-SURGICAL COMPLETE ATRIOVENTRICULAR BLOCK IN CHILDREN AND PREDICTORS OF PACEMAKER IMPLANTATION (YOUNG INVESTIGATOR AWARD COMPETITION)

Objectives
We aimed to evaluate natural course and predictors of pacemaker (PM) implantation in a nation-wide cohort of pediatric patients with non-surgical complete atrioventricular block (CAVB).
Background
Data on natural history of CAVB in children are scarce and criteria for PM implantation are based on low levels of evidence.
Methods
All children with CAVB in absence of structural heart disease presenting between 1977-2016 were retrospectively identified yielding 95 subjects aged median 4.05 years at first presentation with follow-up median 0.80 (IQR 0.02-6.82) years. PM implantation was performed according to available guidelines. Serial 24-hour Holter recordings and echocardiograms were reviewed. Predictors of PM implantation performed >1 month after first presentation were evaluated.
Results
Minimum and mean 24-hour heart rates (HR) and maximum RR intervals had a non-linear correlation with age (p58 BPM (>75 centile) had high probability of freedom from PM within the subsequent 5 years (91.7 vs 44.4 %, p<0.001).
Conclusions
Pediatric patients with CAVB showed age-dependent decrease in HR, moderate LV dilation and preserved LV function. Probability of subsequent PM implantation could be predicted by the HR profile at presentation defining a low-risk group and allowing for individualized follow-up.