Objective To compare left ventricular (LV)synchronization of direct His-bundle pacing (DHBP)and right ventricular apical pacing (RVAP)with two-dimensional speckle tracking imaging (2D-STI)and tissue Doppler imaging (TDI),and discuss the diagnostic value of 2D-STI and TDI in evaluation of left ventricular systolic synchronicity.Methods Twenty-four patients implanted with DHBP and RVAP were observed.Conventional echocardiography examination were undergone both at the mode of DHBP or RVAP respectively.The time to peak radial strain of LV 1 8 segments were derived from the parasternal short-axis views by 2D-STI,then calculated the standard deviations (SD ) and the maximal temporal difference of LV 1 8 segments (Trs-SD and Trs-Dif),and the interval of time to peak radial strain between the anteroseptal wall and the posterior wall (Tas-post).The time to peak systolic velocity of LV 12 segments were derived from the apical axis views by TDI.The SD and the maximal temporal difference of 1 2 segments (Ts-SD and Ts-Dif)were calculated as the LV dyssynchrony index.Results All the systolic synchrony parameters derived from 2D-STI and TDI were more significantly shortened in DHBP than in RVAP (all P <0.01).For DHBP,the detection rate of LV synchronization was higher by 2D-STI than by TDI.For RVAP the detection rate of LV dyssynchronization was also higher by 2D-STI than by TDI with RVAP lead (all P <0.05).Conclusions DHBP is more beneficial than RVAP in LV syschronization and LV function,RVAP may induce left ventricular systolic asynchrony.Both 2D-STI and TDI can assess the LV synchronization quantitatively,but 2D-STI may be more superior on the detection rate than TDI.