Evaluation of cardiac synchrony in patients with permanent left bundle branch area pacing by tissue Doppler imaging

Abstract

Objective To compare and analyze the synchrony of cardiac contraction when left bundle branch area pacing (LBBP) using tissue Doppler imaging (TDI). Methods Twenty-four patients with LBBP and 20 patients with right ventricular pacing (RVP) were enrolled in the study. Among them, 35 cases were diagnosed as sick sinus syndrome (SSS) and 9 cases were diagnosed as Ⅱ or Ⅲ degree atrioventricular block (AVB) before operation. Echocardiographic images were collected with ventricular pacemaker-on, and patients with SSS in LBBP group under the condition of pacemaker program control also collected the image of self-conduction. TDI was used to measure time of the peak velocity (Ts) of myocardial contraction in the left ventricular 12 segments, right ventricle 2 segments, and atrial 3 walls.The difference between the basal segment of left ventricular lateral wall and right ventricular free wall (Ts-LV-RV), the mean value of the right ventricular 2 segments (Ts-2-RV), the average(Ts-12-LV) and standard deviation (Tsd-12-LV) of the left ventricular 12 segments, and the difference in peak systolic time among 3 walls TAL-R, TAI-R, TAL-I were calculated. Results Compared with the RVP pacing state, the parameters of left ventricular systolic synchrony in LBBP pacing were shortened, and the difference was statistically significant (P 0.05). Conclusions Left ventricular systolic synchrony is superior to RVP in LBBP pacing, and left/right ventricular systolic synchrony and cardiac function are not different from self-conduction. LBBP is a new physiological pacing. TDI is able to quantitatively assess cardiac systolic synchrony. Key words: Echocardiography; Cardiac mechanical synchronization; Left bundle branch area pacing; Physiological pacing