Abstract 11164: Better Electromechanical Synchrony During Left Bundle Branch Pacing and His Bundle Pacing as Compared to Right Ventricular Pacing in Atrioventricular Block

Abstract

Objectives: To compare electromechanical ventricular synchrony when pacing from different sites including right ventricular apex pacing (RVAP), right ventricular septum pacing (RVSP), His Bundle pacing (HBP), left bundle branch pacing (LBBP) and RVSP during unipolar pacing from the ring electrode of LBBP lead (RVSP ring ) in each patient during implantation. Methods: Twenty patients with complete atrioventricular block (AVB) indicated for dual-chamber pacemaker implantation were included. Unipolar pacing at different sites including RVAP,RVSP,HBP,LBBP and RVSP ring were successively performed in each patient while pacing characteristics and echocardiogram parameters were collected and compared. Results: Similar to HBP, narrower paced QRSd was found in LBBP as compared to RVSP ring , RVSP and RVAP(p<0.001). LBBP showed comparable pacing parameters to RVAP or RVSP and were significantly better than HBP, with maintained cardiac function. For ventricular mechanical synchrony, TS-12-SD was significantly improved in LBBP(27.00±21.53ms) than RVAP(54.05±34.21ms, p=0.004) and RVSP(47.56±33.26ms, p=0.029) but similar to HBP or RVSP ring . Among these pacing strategies, negative values of interventricular mechanical delay(IVMD) were only identified in LBBP(-20.16±18.47ms), significantly different from RVAP(33.68±30.98ms), RVSP (21.68±22.02ms), HBP (4.74±19.04ms) and RVSP ring (14.56±26.76ms(all p<0.001). Using Pearson’s analysis, Sti-LVAT was found to be positively corelated with QRS, IVMD, TS-12-SD, LVEDV and LVESV while a negative relationship could be observed for LVEF. Conclusions: Similar to HBP, LBBP achieved better electrical and mechanical left ventricular synchrony than conventional RV pacing. For interventricular synchrony, only LBBP initiated earlier LV activation than RV among these pacing strategies, in consistent with the RBBB pattern of paced QRS during LBBP.