Objective To evaluate early left atrial function after left bundle branch pacing (LBBP) by two-dimensional speckle tracking imaging (2D-STI). Methods Fourty-seven patients after pacemaker implantation were rolled in

including 26 cases of LBBP and 21 cases of right ventricular septum pacing (RVP)

conventional echocardiography were performed one month after implantation. Twenty healthy persons were enrolled as control group. Left atrial reservoir strain (LASr)

left atrial conduit strain (LAScd)

left atrial contraction strain (LASct)

global longitudinal strain (GLS) and apical two

three and four chamber view global longitudinal strain (GLS-AP2

GLS-AP3

GLS-AP4) were analyzed by 2D-STI to evaluate function of left atrial and ventricular. Standard deviation of time to peak (Tp-SD) and maximum difference of time to peak (Tp-dif) were used to evaluate synchronization of left ventricular. Results Comparison of left atrial function parameters

LASr in patients with LBBP and RVP and LAScd in patients with RVP both decreased with significant differences (P<0.05). Left ventricular function analysis showed that GLS-AP2、GLS-AP3、GLS-AP4 and GLS of LBBP group and RVP group both decreased with significant differences compared with control group. Tp-SD and Tp-dif in RVP increased significantly compared with other groups (P<0.05). Tp-SD and TP-dif of LBBP and RVP group were positively correlated with LAScd. Conclusion 2D-STI technique can be used to evaluate the early left atrial function after left bundle branch pacing. Compared with RVP

LBBP has better left ventricular synchronization

which is conducive to the protection of left atrial conduit function.