NATURAL HISTORY OF NON-SURGICAL COMPLETE ATRIOVENTRICULAR BLOCK IN CHILDREN AND PREDICTORS OF PACEMAKER IMPLANTATION

Objectives
Data on natural history of non-surgical complete atrioventricular block (CAVB) in children are scarce and criteria for pacemaker implantation (PM) are based on low level of evidence. We aimed to evaluate natural course and predictors of PM in a nation-wide cohort of paediatric patients with CAVB.

Methods
All paediatric patients (1977-2016) with CAVB in absence of structural heart disease were identified from institutional database yielding 95 subjects aged median 4.06 years at first presentation. Patients were followed-up for median 0.80 (IQR 0.02-7.07) years providing a total of 347 patient-years for analysis. Holter recordings and echocardiograms were reviewed to asses heart rate profiles, left ventricular (LV) size and shortening fraction (SF). Predictors of PM performed >1 month after first presentation were evaluated.

Results
Absolute minimum and mean 24-hour heart rates and maximum RR intervals had a non-linear correlation with age (p58 BPM (>75 centile of the group) had high probability of freedom from PM within subsequent 5 years (91.7 % vs 41.2 %, p=0.012). Echocardiographic parameters did not predict PM.

Conclusions
Paediatric patients with CAVB show an age-dependent decrease in heart rates, stable degree of LV remodelling and preserved LV function. Need for PM can be predicted by the heart rate profile at presentation defining a low risk group and allowing for stratified follow-up.