RESUMO
Objective:To assess the changes of left ventricular systolic function and global synchronization and myocardial work in patients with left bundle branch pacing (LBBP) by two-dimensional multi-layered speckle tracking imaging.Methods:Forty-two patients with Ⅱ degree Ⅱ type or Ⅲ degree atrioventricular block (AVB) in the Cardiovascular Hospital of Xiamen University from April to December 2019 were selected as pacing group, which were further divided into two groups according to different pacemaker modes: twenty patients with right ventricular septal pacing (RVSP), twenty-two patients with LBBP, and twenty patients with normal ECG and cardiac structure were enrolled as control group. Echocardiography of pacing group and control group was performed and analyzed. The left ventricular subendocardial longitudinal strain peak(LSendo), the middle layer myocardial longitudinal strain peak(LSmid), subepicardial longitudinal strain peak(LSepi), global myocardial longitudinal strain peak(GLS), peak strain dispersion (PSD), global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE) were acquired. The differences among the three groups were analyzed and the high difference indexes were screened by statistical modeling.Results:LSendo in three groups had no difference ( P>0.05). LSmid, LSepi, GLS in the control group, LBBP group and RVSP groups were decreased gradually ( P<0.05). GLS in LBBP group was higher than in RVSP group ( P<0.05). Compared with the control group, the increases of QRS and PSD in LBBP group were not statistically significant ( P>0.05), while the decreases of QRS and PSD in LBBP group were statistically significant compared with the RVSP group ( P<0.05). The values of GCW among three groups had no statistical significance ( P>0.05). Compared with the control group, the decrease of GWI in LBBP group was not statistically significant ( P>0.05), while the increase of GWW and the decrease of GWE were statistically significant ( P<0.05). Compared with the RVSP group, the increases of GWI and GWE and the decrease of GWW in LBBP group were statistically significant ( P<0.05). QRS, LSendo, GLS, LSmid, left ventricular apex rotation to basal rotation peak time(ApexBase period) were the indexes with significant difference among LBBP and RVSP groups and all index characteristics showed better in LBBP than RVSP group. Conclusions:Two-dimensional multi-layered speckle tracking imaging can be used to evaluate the effect of LBBP on left ventricular systolic function and global synchronization and myocardial work. LBBP longitudinal mechanical synchronization is better than right ventricular septal pacing by improving the peak global myocardial longitudinal strain and myocardial work after pacemaker.