Long-term Efficacy And Safety Evaluation Of Left Bundle Branch Pacing In Patients With Third-degree Atrioventricular Block

Objective:To investigate the long-term efficacy and safety of left bundle branch pacing(LBBP)in patients with third-degree atrioventricular block.Methods:1.Forty-nine patients with third-degree atrioventricular block from 2020-01-01 to2020-6-31 in The Affiliated Hospital of Qingdao University who were eligible for pacing indications were selected.According to the different pacing sites,they were divided into two groups.Twenty-four patients were included in the LBBP group.Twenty-five patients were included in the right ventricular septal pacing(RVSP)group.2.Three-dimensional speckle tracking technology was used to collect left ventricular global longitudinal strain(GLS),global radial strain(GRS),and global circumferential strain(GCS)at 1,12 and 18 months after surgery.At the same time,the percentage of the standard deviation of the time when the left ventricular 16 segments reach the minimum systolic volume in the cardiac cycle(Tmsv16-SD/R-R)was calculated.The left ventricular end-diastolic diameter(LVEDD),left ventricular end-systolic diameter(LVESD)and left ventricular ejection fraction(LVEF)of the patients were also collected by conventional echocardiography.3.The N-terminal pro-brain natriuretic peptide(NT-Pro BNP)and QRS duration(QRSd)were measured at 1,12 and 18 months after surgery.And the pacing parameters and related complications of patients were followed up.Results:1.A total of 49 patients were enrolled.There were 24 patients in the LBBP group,with an average age of(63.25±9.40)years old.There were 25 patients in the RVSP group,with an average age of(60.04±9.20)years old.There was no significant difference in baseline data between the two groups(P>0.05).2.Comparison of myocardial strain indexes between the two groups after surgery:GLS in the LBBP group and RVSP group showed an upward trend after surgery.The increase of GLS in the LBBP group was higher than that in the RVSP group.At 18 months after surgery,GLS in the LBBP group was significantly higher than that in the RVSP group [(29.96±4.83)vs(26.48±3.80),p<0.05].GCS also increased gradually in the LBBP group after surgery.In the LBBP group,GCS at 18 months after surgery was significantly higher than that at 1 month after surgery [(29.29±4.39)vs(26.38±3.36),P<0.05].GCS in the RVSP group was no significant change after surgery(P>0.05).There was no significant difference in GCS between the two groups(P>0.05).There was no significant change in GRS between the two groups after surgery(P>0.05).3.Comparison of conventional ultrasound indexes between the two groups after surgery: The LVEDD,LVESD and LVEF of the LBBP group and the RVSP group remained stable after surgery.And there was no statistical difference between the two groups.4.Comparison of left ventricular electrical and mechanical synchrony between two groups after surgery: Comparison of electrical synchrony: The QRSd in the LBBP group was significantly lower than that of the RVSP group at 1 month after surgery[(107.88±12.69)ms vs(141.36±14.97)ms,P<0.05].And the QRSd duration in the LBBP group remained stable during the 18-months follow-up(P>0.05).The QRSd in the LBBP group was significantly shorter than that in the RVSP group at 18 months after surgery[(108.29±11.99)ms vs(143.64±15.70)ms,P < 0.05].Comparison of mechanical synchrony: Tmsv16-SD/R-R remained stable after surgery in the LBBP group(P>0.05).Tmsv16-SD/R-R in the LBBP group was significantly lower than that in the RVSP group at 18 months after surgery [(4.28±0.68)vs(6.34±1.70),P<0.05].5.Comparison of NT-Pro BNP between the two groups after surgery: NT-pro BNP in both LBBP and RVSP groups showed a downward trend after surgery(P<0.05).At 1month after the surgery,NT-pro BNP in the LBBP group was significantly lower than that in the RVSP group [(220.79±9.74)pg/ml vs(249.96±8.89)pg/ml,P<0.05].At 18 months after surgery,NT-pro BNP in the LBBP group decreased from(220.79±9.74)pg/ml to(148.08±5.93).At 18 months after surgery,NT-pro BNP in the RVSP group decreased from(249.96±8.89)pg/ml to(178.28±5.86)pg/ml.And 18 months after the surgery,NT-pro BNP in the LBBP group was significantly lower than that in the RVSP group(P<0.05).6.All patients were successfully paced.The pacing parameters of all patients were stable in the long-term follow-up after surgery.There were no complications such as infection,lead dislocation and perforation in all patients.Conclusion:As an emerging pacing method,LBBP can significantly improve the left ventricular electromechanical synchronization after surgery.And left ventricular systolic function after LBBP was significantly better than that after RVSP.And the pacing parameters were stable after LBBP.