The Fesaibility Of His Bundle Pacing In Patients With Narrow QRS Complex Who Required High Percentage Of Ventricular Pacing

Objectives: To investigate the feasibility,safety of His bundle(HB)pacing(HBP)among patients with narrow QRS complex who required high percentage of ventricular pacing.Methods:Patients with narrow QRS complex who required high percentage of ventricular pacing and underwent an attempt at permanent HBP in General Hospital of Shenyang Military Region from March 2016 to December 2017 were enrolled in this study in clinical roitine practice.All HBP procedures were performed by the same physician.The output criteria or the circle length criteria was used as the gold standard to determine the selective and non-selective HBP and right ventricular muscle pacing(RVP)around HB.The electrophysiological characteristics of block sites,success rate of HBP on different experience stage,the pacing percentage,the threshold and stability of HBP lead were analyzed.Results:Among 72 patients,atrial fibrillation with slow ventricular rate was diagnosed in 28 patients and complete atrioventricular block was diagnosed in the other 44 patients.The average heart rate was 50±10(30-76)beats per minutes and the duration of QRS complex was 89.9±10.7(70-115)ms.The total success rate of HBP was 81.9%(59/72),92.9%(26/28)in patients with atrial fibrillation and slow ventricular rate and 75.0%(33/44)in patients with complete atrioventricular block,26 patients with block position in proximal and/or above of HB,the HBP procedures were succeful operated in 22(22/26,84.6%)patients,12 patients with block position in the middle of HB,the HBP procedures were succeful operated in 9(9/12,75.0%)patients,6 patients with block position in the distal of HB,the HBP procedures were succeful operated in 2(2/6,33.3%)patients.Among 59 patients who had HBP,started pacing test at 5.0V/0.5ms,7 patients performed S-HBP,the other 52 patients performedNS-HBP,when pacing output descend,27 patients performed S-HBP,20 patients performed RVP,5 patients performed NS-HBP.The success rate of HBP during HBP learning period in the first 30 procedures was 70.0%(21/30)and ascends to 90.5%(38/42)in the latter 42 procedures,there were distinguish difference in statistically,P=0.03.in the first 30 procedures,16 patients were atrial fibrillation with slow heart rate,14 patients had HBP,the success tate was 87.5%(14/16),other 14 patients were complete atrialventricular block,7 patients had HBP,the success tate was 50.0%(7/14).the latter 42 procedures,12 patients were atrial fibrillation with slow heart rate,all of them had HBP,other 30 patients with complete atrialventricular block,26 patients had HBP,the success tate was 86.7%(26/30),the rate of success ascend distinguish,P=0.03.The success rate of HBP during HBP learning period in the first30 procedures was 70.0%(21/30)and ascends to 86.7%(38/42)in the latter 42 procedures.Mean fluoroscopy time of a success HBP procedure was 5.8±3.6 min.Backup right ventricular pacing lead was implanted in 30 patients.The average percentage of HBP was more than 99%(85%-100%).Elevation of HBP threshold(value of 3.5V/0.5 ms)was observed in four patient during follow-up.There was no lead dislodgment during follow-up and no complication related to HBP procedure.Conclusion:HBP in patients with narrow QRS complex who required high percentage of ventricular pacing was feasible and was safe and stable after procedure.The success rate was 81.9%.During 12 months follow up,HB pacing thresthold were srable.No one had electrode displacing and complaction about pacing.