Seven year experience of leadless pacing systems in a tertiary irish hospital

Background/Introduction

Introduction of leadless pacemaker (LP) systems can bypass issues associated with transvenous pacing devices especially in patients with occlude subclavian veins, fistulas for dialysis, recurrent lead endocarditis, ongoing or intercurrent infections. We audited our 7-year experience with LP systems to assess indications, complication rates, patient outcomes and device performance.

Purpose

We report our experience in managing patients who underwent LP insertion with assessment of indications, procedure complications, pacing parameters and device performance. Follow-up echcardiograms (TEE) were reviewed. Our cohort of LP systems is the largest in a public hospital in Ireland.

Methods

We conducted a retrospective audit of electronic and paper-based patient records for consecutive patients who had LP devices inserted from 2018 to 2025. Records of LP implantation were collected from Heart Rhythm Ireland (HRI), a registry for implanted cardiac devices in Ireland. Data was reviewed from 65 patients who have had either the MICRA VR, MICRA AV or MICRA V2 pacemakers implanted. Implant and follow up device parameters were assessed at 6 weeks, 1 year and most recent follow up date. Paper and electronic records were reviewed to collect demographics, comorbidities, device indication, procedure details and implant parameters. Echocardiography reports were included pre and post-LP, where available.

Results

A consecutive group of 65 patients underwent Antibradycardia Pacing with LP devices. Mean age was 72 (+/-18years). 21 patients were female (32%). Median follow up was 36 months. All but 1 of the devices (98.5%) were implanted under conscious sedation. A significant increase in Tricuspid Regurgitation on TTE was seen in 2 patients (3%). Concerns for pacing induced cardiomyopathy on subsequent TTE was observed in 3 Patients (4.6%). At 7-year follow up, 4 patients had had died from non device related conditions, after a mean survival of 20 months. 7 patients were lost to follow up or followed elsewhere. No patient who had follow up underwent system revisions. There were no Micra removals due to device infection recorded.

Device performance showed stable R Waves at Implant & Most recent follow up. Average implant threshold was 0.5mV at 0.24ms. Mean follow up threshold was 0.55mV at 0.24ms. A repeated measures ANOVA analysis demonstrated no variance in device capture thresholds over follow up reviews (p= 0.60).

2 devices were noted to have premature battery depletion, with 1 patient undergoing a subsequent Micra re-insertion after 18 months. Most recent battery longevity was estimated at > 8 years in 90% of patients (n=48).

Conclusions

Long-term outcomes with LP systems continue to demonstrate a low rate of complications at implantation and at follow up. There Is a low incidence of system revisions, premature battery depletion and device infection. LP devices maintained excellent performance and anticipated battery longevitity.Threshold change - Box & Whisker Plot