Behavior of AV synchrony pacing mode in a leadless pacemaker during variable AV conduction and arrhythmias.

Christophe Garweg,Surinder Kaur Khelae,Joseph Yat Sun Chan,Vincent Splett,Laurence M Epstein,Jonathan P Piccini,Todd Sheldon,Jens Brock Johansen,Venkata Sagi,Mario Pascual,Philippe Ritter,Lluis Mont,Kurt Stromberg,Clemens Steinwender,Nina Kristiansen,Larry Chinitz,Rik Willems

doi:10.1111/jce.15061

Abstract

IntroductionMARVEL 2 assessed the efficacy of mechanical atrial sensing by a ventricular leadless pacemaker, enabling a VDD pacing mode. The behavior of the enhanced MARVEL 2 algorithm during variable atrio‐ventricular conduction (AVC) and/or arrhythmias has not been characterized and is the focus of this study.MethodsOf the 75 patients enrolled in the MARVEL 2 study, 73 had a rhythm assessment and were included in the analysis. The enhanced MARVEL 2 algorithm included a mode‐switching algorithm that automatically switches between VDD and ventricular only antibradycardia pacing (VVI)‐40 depending upon AVC status.ResultsForty‐two patients (58%) had persistent third degree AV block (AVB), 18 (25%) had 1:1 AVC, 5 (7%) had variable AVC status, and 8 (11%) had atrial arrhythmias. Among the 42 patients with persistent third degree AVB, the median ventricular pacing (VP) percentage was 99.9% compared to 0.2% among those with 1:1 AVC. As AVC status changed, the algorithm switched to VDD when the ventricular rate dropped less than 40 bpm. During atrial fibrillation (AF) with ventricular response greater than 40 bpm, VVI‐40 mode was maintained. No pauses longer than 1500 ms were observed. Frequent ventricular premature beats reduced the percentage of AV synchrony. During AF, the atrial signal was of low amplitude and there was infrequent sensing.ConclusionThe mode switching algorithm reduced VP in patients with 1:1 AVC and appropriately switched to VDD during AV block. No pacing safety issues were observed during arrhythmias.

Highlights

Micra atrial tracking using a ventricular accelerometer (MARVEL) 2 assessed the efficacy of mechanical atrial sensing by a ventricular leadless pacemaker, enabling a VDD pacing mode
The enhanced MARVEL 2 algorithm included a mode‐switching algorithm that automatically switches between VDD and ventricular only antibradycardia pacing (VVI)‐40 depending upon atrio‐ventricular conduction (AVC) status
Among the 42 patients with persistent third degree AV block (AVB), the median ventricular pacing (VP) percentage was 99.9% compared to 0.2% among those with 1:1 AVC

Summary

Introduction

MARVEL 2 assessed the efficacy of mechanical atrial sensing by a ventricular leadless pacemaker, enabling a VDD pacing mode. Implantation of a single‐chamber ventricular pacing device is limited to 14%–32% of all pacemaker implants as the maintenance of atrio‐ventricular synchrony (AVS) is preferred in patients with high degree AV block and preserved sinus rhythm.[6,7]. The Micra atrial tracking using a ventricular accelerometer (MARVEL) 2 study demonstrated high AV synchronous pacing at rest (mean 89.2%) in patients previously implanted with a ventricular leadless pacemaker and presenting with third degree AV block and normal sinus rhythm between 60 and 100 beats per minute.[8]

Methods

Results

Conclusion