Transvenous, Extraction, Leadless: Opportunities in the New Era of Leadless Pacemakers

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EP LAB DIGEST. 2024;24(11):1,10-11.

Samira Teeri, MD; Nebu Alexander, MD; Cyrus Hadadi, MD
MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC

Lead malfunction is a common complication of traditional transvenous pacemakers. Here, we describe a patient with a dual-chamber transvenous permanent pacemaker originally implanted due to complete heart block who experienced lead fracture and noise, prior unsuccessful lead extraction attempt, and recurrent syncope. She declined further extraction efforts and instead underwent successful implantation of a right ventricular (RV) leadless pacemaker subsequently followed by an upgrade to a true dual-chamber leadless pacemaker.

Case Presentation

An 80-year-old woman presented with complications related to her dual-chamber transvenous permanent pacemaker, implanted in 2002 and status post generator exchange in 2012. Her other past medical history included hypertension, hyperlipidemia, hypothyroidism, and osteoporosis. 

She experienced RV lead malfunction with fracture and recurrent lead noise, which led to an unsuccessful lead extraction in 2016 and subsequent abandonment of the RV lead with lead locking tools remaining inside the capped lead. A new RV lead was instead implanted at that time. This new lead was similarly compromised with noise, inappropriate inhibition, pauses, and syncope.

She was referred for consideration of extraction and reimplantation vs leadless pacemaker. Twelve-lead electrocardiogram (ECG) demonstrated a

ventricular paced rhythm at 61 beats per minute (bpm) (Figure 1). Device interrogation revealed increased RV lead noise, noise reversion, and inhibition resulting in inappropriate failure to output. Atrial parameters were unremarkable. Ventricular parameters were significant for an elevated capture threshold of 1.75 V at 0.4 ms, and labile impedances were consistent with impending fracture. We believe the recurrent fractures were due to the right-sided nature of the implant, tortuous vasculature, and the patient’s active lifestyle.  

After shared decision-making and informed consent, the patient elected against further extraction attempts. She chose instead to proceed with implantation of a RV leadless permanent pacemaker (AVEIR VR, Abbott), with plans for eventual upgrade to a dual-chamber leadless pacemaker system (AVEIR DR, Abbott) when commercially available.

The main challenge during the time of implantation was to “thread the needle” and place the leadless pacemaker between the 2 transvenous ventricular leads in situ such that the implantation site was safely on the septum without lead-leadless pacemaker interference. 

The AVEIR catheter was advanced through the 25 French introducer sheath to the right atrium, and gently navigated through the tricuspid valve

and into the RV (Figure 2). Contrast-enhanced cine images in left and right anterior oblique projections confirmed appropriate low septal positioning (Figure 3). Passive mapping demonstrated excellent injury current.

The leadless pacemaker was advanced into the septal myocardium using clockwise rotation of its helix, as confirmed by fluoroscopy. Excellent active injury current was noted, indicating effective myocardial capture, with optimal sensing, impedance, and capture thresholds. The device was released from the catheter (Figure 4), which, along with the introducer sheath, was then removed. Hemostasis was achieved using a figure-of-8 suture and manual pressure. There were no complications and the patient was discharged to home without incident.

At her postoperative visit 1 week after implant, the patient was doing well. Her syncopal symptoms had completely resolved. Interrogation of the leadless pacemaker demonstrated normal function with a ventricular threshold of 0.75 V at 0.4 ms, R wave amplitude improved to 12.5 mV from 4.5 mV at implant, and stable impedance.

When the AVEIR DR became commercially available 3 months after her first procedure, the patient presented for implantation of an atrial leadless pacemaker (AVEIR AR, Abbott) and upgraded to a dual-chamber leadless pacemaker system. She again elected against lead extraction but asked to explant the transvenous pacemaker generator from her pacemaker pocket. 

A pigtail catheter was advanced through the introducer sheath, and a contrast venogram was performed to identify the base of the right atrial appendage. The AVEIR catheter was advanced through the introducer sheath and navigated to the anterior base of the right atrial appendage (Figure 5). The implantation procedure was similar to that of the RV device description. Atrial capture, sensing, and impedance parameters were excellent. The device was released, and the deployment catheter was removed from the body. Figure-of-8 sutures were again applied to achieve hemostasis. The pacemaker generator was dissected and removed from the pocket and the chronic leads were capped without incident.

At her next postoperative visit, the patient again reported feeling great. She had no recurrence of any of her previous symptoms. Interrogation of the dual-chamber leadless pacemaker revealed normal function in DDDR mode with a rate of 60-130 bpm. Over the device’s lifetime, atrial pacing was 24% and ventricular pacing was 14%. The atrial threshold was 0.75 V at 0.2 ms, R wave amplitude at 3.0 mV, and impedance was 300 ohms. The ventricular threshold was 1.0 V at 0.4 ms, with impedance at 370 ohms. The maximum tracking rate was increased to 140 bpm, and sensitivity for rate response was optimized. 

The patient has continued to do well and is pleased with her outcome.

Discussion

While traditional pacemakers have seen evolutionary improvements in battery life and quality over the years, they continue to present challenges related to the presence of transvenous leads and the subcutaneous pocket, including complications such as infection, pocket hematoma, lead fractures, lead displacement, and cardiac tamponade. The FOLLOWPACE study,¹ published in 2012, demonstrated that more than 12% of patients who underwent transvenous pacemaker implantation experienced a complication within 2 months. Most complications involved the surgical pacemaker pocket and transvenous leads.

Lead revision and extraction is a safe procedure when performed in a high-volume center of excellence with skilled lead extraction specialists. Periprocedural complications are low. In our case, we felt that the patient would be an excellent candidate for redo lead extraction. However, given her earlier failed attempt at another institution, she elected against extraction. 

The leadless permanent pacemaker system was developed to address complications associated with traditional pacemakers by eliminating the need for leads and an external device pocket. The single-chamber leadless pacemaker is a self-contained generator and electrode system implanted directly into the RV. It is inserted via a femoral vein transcatheter approach, requiring no chest incision or subcutaneous generator pocket. This technology is beneficial to all patients indicated for pacemaker therapy. 

In particular, leadless pacing options are invaluable in patients with limited upper venous access, patients with a history of lead-related complications such as lead displacement or lead fracture, and patients with higher risk of lead infection. 

In 2016, the Micra Transcatheter Pacemaker System (Medtronic) was the first leadless pacemaker to receive approval from the US Food and Drug Administration (FDA). The AVEIR VR Single-Chamber Leadless Pacemaker System (Abbott) received FDA approval in 2022. Clinical studies have demonstrated the effectiveness and safety of these leadless systems. The LEADLESS trial,² a prospective non-randomized study involving 33 patients, showed an implant success rate of 97% and an overall complication-free rate of 94%. Additionally, the LEADLESS II-Phase 2 trial,³ an international multicenter study with 200 participants, reported a success rate of 95.9% and 96.0% freedom from serious adverse device effects.

In 2023, the FDA approved the AVEIR Dual-Chamber Leadless Pacemaker System (Abbott). This approval extends the technology’s applicability to a broader range of patients, including those with sinus node and atrioventricular (AV) node dysfunction. A prospective, multicenter, single-group study by Knops et al in 2023 involving 300 patients receiving a dual-chamber leadless pacemaker reported an implant success rate of 98.3% and a complication-free rate of 90.3%.⁴ The electrical performance success rate was 90.2%, and at least 70% AV synchrony was achieved in 97.3% of the patients.

For patients with an existing single-chamber leadless pacemaker who need to upgrade to a dual-chamber leadless pacemaker, such as in this case, a study by Bongiorni et al reported a successful upgrade rate of 89% in a cohort of 36 patients.⁵

Our patient was an appropriate candidate for a leadless pacemaker system due to recurrent lead noise and a prior unsuccessful RV lead extraction. She initially received the single-chamber leadless RV pacemaker (AVEIR VR) and, following FDA approval of the dual-chamber leadless pacemaker, her device was successfully upgraded by adding an atrial leadless pacemaker (AVEIR AR) to ensure AV synchrony. The AVEIR platform allows for versatility of implantation in the right atrium, RV, or both chambers.

Conclusion

This case highlights the successful management of transvenous lead-related complications in a patient with a dual-chamber pacemaker through the use of leadless pacemaker technology, and demonstrates a successful upgrade from a single-chamber to a dual-chamber leadless pacemaker. It is likely that lead extraction and leadless pacemaker specialists and centers of excellence will be referred more “extract transvenous and implant leadless” cases as the awareness of this new era of true dual-chamber leadless pacemakers spreads. 

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest and report no conflicts of interest regarding the content herein. Dr Hadadi reports he is a paid consultant for Abbott. 

References

1. Udo EO, Zuithoff NP, van Hemel NM, et al. Incidence and predictors of short- and long-term complications in pacemaker therapy: the FOLLOWPACE study. Heart Rhythm. 2012;9(5):728-735. doi:10.1016/j.hrthm.2011.12.014

2. Reddy VY, Knops RE, Sperzel J, et al. Permanent leadless cardiac pacing: results of the LEADLESS trial. Circulation. 2014;129(14):1466-1471. doi:10.1161/CIRCULATIONAHA.113.006987

3. Reddy VY, Exner DV, Doshi R, et al. Primary results on safety and efficacy from the LEADLESS II-Phase 2 worldwide clinical trial. JACC: Clin Electrophysiol. 2022;8(1):115-117. doi:10.1016/j.jacep.2021.11.002

4. Knops RE, Reddy VY, Ip JE, et al. A dual-chamber leadless pacemaker. N Engl J Med. 2023;388(25):2360-2370. doi:10.1056/NEJMoa2300080

5. Bongiorni MG, Reddy VY, Ip JE, et al. Upgrading a single-chamber leadless pacemaker to a dual-chamber leadless pacemaker system. EP Europace. 2024;26(Suppl_1):euae102.392. doi:10.1093/europace/euae102.392