Optimizing mechanically sensed atrial tracking in patients with atrioventricular-synchronous leadless pacemakers: A single-center experience

BackgroundAtrioventricular (AV)-synchronous single-chamber leadless pacing using a mechanical atrial sensing algorithm produced high AV synchrony in clinical trials, but clinical practice experience with these devices has not yet been described.ObjectiveTo describe pacing outcomes and programming changes with AV-synchronous leadless pacemakers in clinical practice.MethodsConsecutive patients without persistent atrial fibrillation who received an AV-synchronous leadless pacemaker and completed follow-up between February 2020 and April 2021 were included. We evaluated tracking index (atrial mechanical sense followed by ventricular pace AM-VP divided by total VP), total AV synchrony (sum of AM-ventricular sense AM-VS, AM-VP, and AV conduction mode switch), use of programming optimization, and improvement in AV synchrony after optimization.ResultsFifty patients met the inclusion criteria. Mean age was 69 ± 16.8 years, 24 (48%) were women, 24 (48%) had complete heart block, and 17 (34%) required ≥50% pacing. Mean tracking index was 41% ± 34%. Thirty-five patients (70%) received ≥1 programming change. In 36 patients with 2 follow-up visits, tracking improved by +9% ± 28% (P value for improvement = .09) and +18% ± 19% (P = .02) among 15 patients with complete heart block. Average total AV synchrony increased from 89% 67%, 99% to 93% 78%, 100% in all patients (P = .22), from 86% 52%, 98% to 97% 82%, 99% in those with complete heart block (P = .04), and from 73% 52%, 80% to 78% 70%, 85% in those with ≥50% pacing (P = .09).ConclusionIn patients with AV-synchronous leadless pacemakers, programming changes are frequent and are associated with increased atrial tracking and increased AV synchrony in patients with complete heart block. Atrioventricular (AV)-synchronous single-chamber leadless pacing using a mechanical atrial sensing algorithm produced high AV synchrony in clinical trials, but clinical practice experience with these devices has not yet been described. To describe pacing outcomes and programming changes with AV-synchronous leadless pacemakers in clinical practice. Consecutive patients without persistent atrial fibrillation who received an AV-synchronous leadless pacemaker and completed follow-up between February 2020 and April 2021 were included. We evaluated tracking index (atrial mechanical sense followed by ventricular pace AM-VP divided by total VP), total AV synchrony (sum of AM-ventricular sense AM-VS, AM-VP, and AV conduction mode switch), use of programming optimization, and improvement in AV synchrony after optimization. Fifty patients met the inclusion criteria. Mean age was 69 ± 16.8 years, 24 (48%) were women, 24 (48%) had complete heart block, and 17 (34%) required ≥50% pacing. Mean tracking index was 41% ± 34%. Thirty-five patients (70%) received ≥1 programming change. In 36 patients with 2 follow-up visits, tracking improved by +9% ± 28% (P value for improvement = .09) and +18% ± 19% (P = .02) among 15 patients with complete heart block. Average total AV synchrony increased from 89% 67%, 99% to 93% 78%, 100% in all patients (P = .22), from 86% 52%, 98% to 97% 82%, 99% in those with complete heart block (P = .04), and from 73% 52%, 80% to 78% 70%, 85% in those with ≥50% pacing (P = .09). In patients with AV-synchronous leadless pacemakers, programming changes are frequent and are associated with increased atrial tracking and increased AV synchrony in patients with complete heart block.