Differential effects of the site of permanent epicardial pacing on left ventricular synchrony and function in the young: implications for lead placement

Abstract

To analyse left ventricular (LV) synchrony and function with respect to the epicardial pacing site in the young. Left ventricular function and synchrony (M-mode, speckle tracking) were evaluated during mid-term follow-up in 32 children with complete non-surgical (n = 15) or surgical (n = 17) atrioventricular block (structural heart disease in 21/32) paced from LV apex (n = 19), right ventricular (RV) apex (n = 7), and RV free wall (n = 6), respectively. Data are in the following order: LV apical, RV apical, and RV free wall pacing. Septal to posterior wall motion delay (SPWMD) = median 0, 69, and 136 ms (P < 0.001), septal to lateral mechanical delay = 54 +/- 29, 73 +/- 24, and 129 +/- 70 ms (P = 0.001), apical to basal mechanical delay = 96 +/- 37, 106 +/- 50, and 79 +/- 18 ms (P NS), and LV ejection fraction (LVEF) = 57 +/- 9, 49 +/- 12, and 33 +/- 10% (P < 0.001), respectively. Left ventricular ejection fraction correlated negatively with SPWMD (R(2) = 0.454, P < 0.001) and septal to lateral mechanical delay (R(2) = 0.320, P < 0.001) but not with apical to basal mechanical delay. Right ventricular free wall pacing (P = 0.014) and SPWMD (P = 0.044) were negative multivariable predictors of LVEF. Compared with other sites, LV apical pacing preserves septal to lateral LV synchrony and systolic function and may be the preferred epicardial pacing site in the young.