Diastolic Function in Paced Children with Cardiac Defects: Septum vs Apex

In children with structural congenital heart disease (CHD), the effects of chronicventricular pacing on diastolic function are not well known. On the other hand, thebeneficial effect of septal pacing over apical pacing is still controversial.The aim of this study was to evaluate the influence of different right ventricular(RV) pacing site on left ventricular (LV) diastolic function in children with cardiacdefects.Twenty-nine pediatric patients with complete atrioventricular block (CAVB) and CHDundergoing permanent pacing were prospectively studied. Pacing sites were RV apex (n= 16) and RV septum (n = 13). Echocardiographic assessment was performed beforepacemaker implantation and after it, during a mean follow‑up of 4.9 years.Compared to RV septum, transmitral E-wave was significantly affected in RV apicalpacing (95.38 ± 9.19 vs 83 ± 18.75, p = 0.038). Likewise, parameters at the lateralannular tissue Doppler imaging (TDI) were significantly affected in children paced atthe RV apex. The E´ wave correlated inversely with TDI lateral myocardial performanceindex (Tei index) (R²= 0.9849, p ≤ 0.001). RV apex pacing (Oddsratio, 0.648; confidence interval, 0.067-0.652; p = 0.003) and TDIlateral Tei index (Odds ratio, 31.21; confidence interval,54.6-177.4; p = 0.025) predicted significantly decreased LV diastolic function.Of the two sites studied, RV septum prevents pacing-induced reduction of LV diastolicfunction.