Safety and efficiency of ventricular pacing prevention with an AAI-DDD changeover mode in patients with sinus node disease or atrioventricular block: impact on battery longevity—a sub-study of the ANSWER trial

Abstract

AimsThis ANSWER (EvaluAtioN of the SafeR mode in patients With a dual chambER pacemaker indication) sub-study assesses safety and effectiveness of SafeR™ and the impact of ventricular pacing (VP) prevention on anticipated device longevity and replacement rate.Methods and resultsPatients implanted for atrioventricular block (AVB, n = 310) or sinus node dysfunction (SND, n = 336) were randomly assigned to SafeR (n = 314) or DDD (n = 318) and followed for 36 months. Safety, median VP, estimated device longevity (mean difference, 95% confidence interval [CI]), and anticipated replacement rates were analysed by pacing mode and implant indication. No difference in mortality, syncope, or mode intolerance was observed between randomization groups regardless of the indication. Ventricular pacing on SafeR vs. DDD was 11.5 vs. 93.6% in the overall population (P < 0.001), 89.2 vs. 83.8% in permanent AVB (P = 0.944), 53.5 vs. 98.2% in intermittent AVB (P < 0.001), and 2.2 vs. 84.7% in SND (P < 0.001). Anticipated median device longevity increased on SafeR by 14 [Q1 10; Q3 17] months [10; 17] (P < 0.001) in the overall population, 9 months [−5; 22] (P = 0.193) in permanent AVB, 14 months [8; 19] (P < 0.001) in intermittent AVB, and 14 months [9; 19] (P < 0.001) in SND. In intermittent AVB and SND, prolonged estimated battery longevity translated into the prevention of one anticipated replacement in at least 23% of patients.ConclusionSafeR was effective in reducing VP in intermittent AVB and in SND. No effect was observed in permanent AVB. No safety issue was observed. Ventricular pacing reduction by SafeR translated into relevant estimated prolongation of device longevity and anticipated reduction of required replacements.

Reducing Ventricular Pacing Frequency in Patients With Atrioventricular Block

“…Importantly, no differences in the occurrence of death, syncope, or pacing mode intolerance were observed between groups and implant indications. 13 None of the syncopal events reported in the ANSWER study was related to a recorded complete AVB episode. The event-related analysis of stored electrograms did not reveal any ventricular arrhythmias prompted by SafeR changeovers.…”

“…In the ANSWER study, the significant VP reduction achieved by the SafeR pacing mode when compared with standard DDD mode translated into an additional calculated gain of about 1 year in device longevity (130.6±23.4 months and 117.0±20.0 months, respectively). 13 This potential benefit was similar in SND and intermittent AVB patients. In contrast, in patients with permanent AVB, there was no noticeable effect on device longevity.…”

“…These aspects have been investigated in CAN-SAVE R (Canadian Multi-Centre Randomised StudySpontaneous Atrioventricular Conduction Preservation) 15,16 and in ANSWER (Evaluation of the SafeR™ Mode in Patients With Dual-Chamber Pacemaker Indication). 13,14 The CAN-SAVE R study 15,16 included 373 patients with indications for DDD pacemakers in 10 Canadian centers. Patients were randomized 1:1 to SafeR TM or DDD pacing with a long AV delay (250 ms); SND was present in 73% (81% of whom had no concomitant AVB) and AVB in 41% (66% of whom had no concomitant SND).…”

“…The ANSWER study 13,14 enrolled 650 consecutive patients with a pacemaker indication at 43 European centers and randomized them to programming either the SafeR algorithm or conventional DDD pacing. Approximately half of the population had SND (52%) or AVB (48%); the vast majority of patients with AVB had an intermittent AVB.…”

“…Because the most common indication for permanent pacing is intermittent or persistent complete atrioventricular block (AVB) 7 (Web Table 3-ESC GDL 2013); the value of reducing VP has not been tested adequately in this patient group until recently (Table 1). [9][10][11][12][13][14][15][16][17][18][19][20][21][22] New studies have evaluated the use of an algorithm limiting the frequency of VP in patients with advanced or complete AVB (Table 1). The purpose of the present review is to report the recent apparently contradictory data suggesting more aggressively adopting algorithms that reduce the frequency of ventricular pacing in patients with AVB-a population for whom we have typically programmed continuous and uninterrupted ventricular pacing.…”