Comparison Of Left Heart Function Between Left Bundle Branch Pacing And Right Ventricular Septal Pacing By Three-dimensional Speckle-tracking Technology

Objective:To explore the effects of two pacing methods on cardiac structure and function,comparing the left heart function changes between left bundle branch pacing(LBBP)group and right ventricular septal pacing(RVSP)group by three-dimensional speckletracking technology.Methods:Forty patients diagnosed with third-degree atrioventricular block and meeting the inclusion and exclusion criteria from September 2019 to October 2020 were included,twenty patients underwent LBBP,twenty patients underwent RVSP.Three-dimensional speckle-tracking echocardiography(3D-STE)and two-dimensional speckle-tracking echocardiography(2D-STE)were performed to evaluate left heart function.2DE and3 DE images were acquired before and at the 4-month reexamination after implantation in all patients,Tomtec analysis software was used offline to obtain left atrial maximum volume(LAVmax),left atrial minimum volume(LAVmin),left atrial presystolic volume(LAVp),left atrial total ejection fraction(LATEF),left atrial active ejection fraction(LAAEF),left atrial passive ejection fraction(LAPEF),left atrial expansion index(LAEI),left atrial longitudinal strain during reservoir phase(LASr),left atrial longitudinal strain during conduit phase(LAScd),left atrial longitudinal strain during contraction phase(LASct),left ventricular end-systolic volume(LVESV),left ventricular end-diastolic volume(LVEDV),left ventricular ejection fraction(LVEF),left ventricular global longitudinal strain(LVGLS),left ventricular global circumferential strain(LVGCS),left ventricular global radial strain(LVGRS),left ventricular global area strain(LVGAS).After calculation of body surface area(BSA)correction,the corresponding left atrium maximum volume index(LAVI),left ventricular end-systolic volume index(LVESVI)and left ventricular end-diastolic volume index(LVEDVI)were obtained.The strain data were expressed as absolute values for description and statistics in this study.All data were statistically analyzed using SPSS 26.0.Results:1.There was no significant difference in the general clinical data and preoperative echocardiographic indicators between the two groups(P > 0.05);2.After implantation,LAVmax,LAVmin,LAVI,LAVp,LVEDV,LVESV,LVEDVI,LVESVI,LVEF,LASr,LASct,LVGLS,LVGRS were improved in both groups.LAEI,LATEF,LAAEF were increased in the RVSP group,and LVGCS,LVGAS were increased in the LBBP group(P < 0.05);3.LASr of the LBBP and the RVSP group after implantation were(27.21 ± 8.52)% and(21.38 ± 6.01)%,LASct were(9.39 ± 4.96)% and(6.42 ± 3.33)%.LASr and LASct of the LBBP group were increased compared with the RVSP group(P< 0.05);4.LVESVI of the RVSP group was increased compared with the LBBP group,LVEF of the LBBP and the RVSP group after implantation were [55.87(53.25,58.49)]% and [53.52(50.83,56.21)]%,LVEF of the LBBP group was higher than that of the RVSP group(P < 0.05);5.LVGLS of the LBBP and the RVSP group after implantation were(21.29 ± 3.41)% and(18.90 ± 3.50)%,LVGLS of the LBBP group was higher than that of the RVSP group(P < 0.05);6.There was no significant difference in LAVmax,LAVmin,LAVp,LAVI,LATEF,LAAEF,LAPEF,LAEI,LAScd between the LBBP group and the RVSP group after implantation(P > 0.05);7.LVEDV,LVESV,LVEDVI,LVGCS,LVGRS,LVGAS in the LBBP group were not significantly different in the RVSP group after implantation(P > 0.05).Conclusion:LBBP and RVSP can improve left atrial and left ventricular function.Compared with traditional RVSP,LBBP can activate the ventricular myocardium more physiologically,and may improve left atrial reserve,systolic function and left ventricular systolic function more significantly in the short term.3D-STE can accurately assess left heart function and is essential for efficacy evaluation of pacemakers after implantation.