Abstract 2905: LV Pacing is Superior to RV Pacing in Children With AV Block: A Multi-Center Study
Introduction: Chronic right ventricular (RV) pacing is associated with deleterious effects in long-term functional and structural outcome. Left ventricular (LV) function may be preserved by pacing from alternative sites. We investigated which pacing site for chronic pacing in children with structurally normal hearts carries least adverse effects on LV function.
Methods: From 15 centers echocardiographic data were retrospectively collected from children (<18 years) with either a congenital or acquired AV block (surgically caused blocks are excluded), undergoing chronic pacing (>1 year) at the RV epicardium (RVepi, n=66), at the RV endocardium (RVendo, n=54) or at the epicardium of the LV free wall (LVepi, n=11). Fractional shortening (LVFS) was calculated as a measure of LV function. LV end-diastolic diameters (LVEDD) were normalized to body surface area (BSA) and expressed as Z-scores. ANCOVA was performed on LVFS and LVEDD by pacing site, with pacing duration and BSA as covariates.
Results: Patient characteristics after chronic ventricular pacing are listed in the table⇓. LVFS was significantly influenced by the site of pacing (p=0.021), as well as by the duration of pacing (p=0.006) and BSA (p=0.014). Post hoc analysis with Sidak correction was performed to compare the differences between the three pacing sites, while correcting for the influences of the duration of pacing and BSA. From this analysis LVFS appeared to be significantly better in children with LV pacing as compared to children with RVendo pacing (p=0.019) and as compared to children with RVepi pacing (p=0.050). LVEDD Z-score was not significantly influenced by the site of pacing (p=0.148), nor by the duration of pacing (p=0.781).
Conclusion: Chronic LV pacing in children with a complete AV block results in a better LV function as compared to RV pacing.