Effect on percentage of right ventricular pacing with different AV dalai

doi:10.3969/j.issn.1672-5301.2017.02.016

Abstract：Objective Several studies have shown that not only unnecessary right ventricular pacing but also inappropriate AV delay could have detrimental effects on heart function.The purpose of this study was to compare the percentage of right ventricular pacing of different AV delay in sick sinus syndrome (SSS) and Mobitz type Ⅱ or complete atrioventricular block (AVB),and to study how to set AV delay individually.Methods Patients who accepted dual chamber pacemaker implantation,were divided into SSS or AVB group from September 2012 to December 2015.All of these pacemakers could work with Automatic Intrinsic Conduction Searching(AICS) or Ventricular Intrinsic Preference(VIP).AV delay was changed and the percentage of right ventricular pacing(VP％) was recorded every two months after implantation.The AV delay for atrial paced/sensed events was 150/170 ms(5286) or 150/200 ms(5816 and 5826)at baseline respectively.After two months,it was extension to maximum delay with 325/350 ms,and was working for two months since that time.After another two months,the pacemakers worked with AICS or VIP.AICS and VIP were set to search automatically for intrinsic R-wave conduction every 5 minutes for 3 cycles,with another 120ms added to the baseline AV delay.The VP％s with each AV delay was compared.Results 79 patients were included this study.38 of them were diagnosed SSS,and 41 were in AVB group.1 patient in SSS group was excluded because of permanent atrial fibrillation was occurred.In SSS group,medians of VP％ at 2nd,4th and 6th month were 37％,3％ and 5％ respectively.While in AVB group,the medians were 83％,50％ and 54％.Maximum delay and AICS/VIP reduced VP％ significantly in both groups(P＜0.05),and the VP％ with maximum delay was lesser than that with AICS/VIP (P＜0.05).Compared to AVB group,VP％ in SSS group was reduced more significantly.Conclusion VP％ can be reduced by longer AV delay.The AV delay should be set individually.It is recommended to implant the pacemakers with AICS/VIP.But it needs more studies to evaluate how to set the AV delay individually.