Very Low Ventricular Pacing Rates Can Be Achieved Safely in a Heterogeneous Pacemaker Population and Provide Clinical Benefits: The CANadian Multi‐Centre Randomised Study‐Spontaneous AtrioVEntricular Conduction pReservation (CAN‐SAVE R) Trial

Abstract

BackgroundIt is well recognized that right ventricular apical pacing can have deleterious effects on ventricular function. We performed a head-to-head comparison of the SafeR pacing algorithm versus DDD pacing with a long atrioventricular delay in a heterogeneous population of patients with dual-chamber pacemakers.Methods and ResultsIn a multicenter prospective double-blinded randomized trial conducted at 10 centers in Canada, 373 patients, age 71±11 years, with indications for dual chamber DC pacemakers were randomized 1:1 to SafeR or DDD pacing with a long atrioventricular delay (250 ms). The primary objective was twofold: (1) reduction in the proportion of ventricular paced beats at 1 year; and (2) impact on atrial fibrillation burden at 3 years, defined as the ratio between cumulative duration of mode-switches divided by follow-up time. Statistical significance of both co-primary end points was required for the trial to be considered positive. At 1 year of follow-up, the median proportion of ventricular-paced beats was 4.0% with DDD versus 0% with SafeR (P<0.001). At 3 years of follow-up, the atrial fibrillation burden was not significantly reduced with SafeR versus DDD (median 0.00%, interquartile range [0.00% to 0.23%] versus median 0.01%, interquartile range [0.00% to 0.44%], respectively, P=0.178]), despite a persistent reduction in the median proportion of ventricular-paced beats (10% with DDD compared to 0% with SafeR).ConclusionsA ventricular-paced rate <1% was safely achieved with SafeR in a population with a wide spectrum of indications for dual-chamber pacing. However, the lower percentage of ventricular pacing did not translate into a significant reduction in atrial fibrillation burden.Clinical Trial RegistrationURL: https://www.clinicaltrials.gov/ Unique identifier: NCT01219621.

Clinical, echocardiographic, and pacing parameters affecting atrial fibrillation burden in patients with tachycardia-bradycardia syndrome

“…Such a hypothesis may explain the correlations between the AV prolongation and AF progression observed in some large studies [12,19]. Moreover, it neatly explains why more sophisticated algorithms of avoiding right ventricular pacing fail to show the clear benefit of further RVp% reduction in terms of AF development [15,20,21]. The benefit of right ventricular pacing avoidance would be compensated in those cases by the detrimental effect of a too long AV delay and greater advancement of the degenerative disease concerning the atria and both nodes in which AV prolongation would be a sign rather than a cause.…”

Cardiac Stimulation in the Third Millennium: Where Do We Head from Here?

“…The SAVE PACE (Search AV Extension and Managed Ventricular Pacing for Promoting Atrioventricular Conduction) trial proved that RV pacing minimization decreases persistent AF compared to standard DDD pacing in patients with SSS [36]. Several other studies with different algorithms for RV pacing minimization enrolled also permanent and intermittent AVB patients, but were unable to convincingly confirm clinical superiority of RV pacing minimization to conventional DDD/DDDR pacing [37][38][39][40].…”

Reducing Ventricular Pacing Frequency in Patients With Atrioventricular Block

“…However, long-term data on the impact of SafeR on the risk of developing adverse cardiac events, including syncope, HF or AF in patients with intermittent or permanent AVB have been lacking until recently. 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.…”

“…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).…”

“…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.…”