Comparative study on ultrasonic assessments of left ventricular systolic synchronicity under different cardiac pacing modes

Abstract

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 18 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 18 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 12 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. Key words: Echocardiography; Cardiac pacing, artificial; Ventricular function, left