Pacemaker Syndrome in the Young:

The aim of this study was to determine if single chamber rate responsive ventricular pacing (VVIR) predisposes growing children to develop pacemaker syndrome (PS), and if so, what are determining factors and/or clinically useful predictors. PS is a constellation of symptoms that result from the lack of consistent AV sequential filling due to atrial contraction against closed AV valves. PS has not been commonly reported in the young. Data from all patients with pacemakers with congenital complete atrioventricular block (CAVB) with normal anatomy, and those with congenital heart disease (CHD), and surgically acquired CAVB were reviewed. Inclusion criteria were normal ventricular function by cardiac ultrasound and 100% VVIR pacing. Of 89 patients with VVIR pacemaker implants, 33 met these criteria. Of these, 19 developed PS. For statistical analysis, chi-square and independent samples t-test was used with significance defined at P < or = 0.05. No consistent association was found between cardiac anatomy, type of CAVB, or age at implant with development of PS. However, PS did correlate with duration of pacing (P = 0.02). The exercise stress test showed significant differences between 100% VVIR-paced patients with and without PS, in terms of work rate (P = 0.002) and measured oxygen consumption (P = 0.01). This study shows that PS appears to be a time related event in younger children with normal ventricular function who are 100% ventricular paced. Thus, this supports VVIR pacing as an adequate and cost-effective initial therapy for symptomatic bradycardia due to CAVB.