Complications of leadless vs conventional (lead) artificial pacemakers - a retrospective review

Six-month Electrical Performance of the First Dual-Chamber Leadless Pacemaker

BACKGROUND

The first dual-chamber leadless pacemaker (DC-LP) system consists of two separate atrial and ventricular devices that communicate to maintain synchronous atrioventricular pacing and sensing. The initial safety and efficacy were previously reported.

OBJECTIVE

Evaluate the chronic electrical performance of the DC-LP system.

METHODS

Patients meeting standard dual-chamber pacing indications were enrolled and implanted with the DC-LP system (Aveir DR, Abbott), including right atrial and ventricular helix-fixation LPs (ALP, VLP). Pacing capture threshold, sensed amplitude, and pacing impedance were collected using the device programmer at prespecified time points from 0-6 months post-implant.

RESULTS

De novo devices were successfully implanted in 381 patients with complete 6M data (62% male; age 69±14 years; weight 82±20 kg; 65% sinus node dysfunction, 30% AV block). ALPs were implanted predominantly in the right atrial appendage anterior base; VLPs primarily at the mid-to-apical right ventricular septum. From implant to 1 month, pacing capture thresholds (0.4 ms pulse width) improved in both ALPs (2.4±1.5 to 0.8±0.8 V, P<0.001) and VLPs (0.8±0.6 to 0.6±0.4 V, P<0.001). Sensed amplitudes improved in both ALPs (1.8±1.3 to 3.4±1.9 mV, P<0.001) and VLPs (8.8±4.0 to 11.7±4.2 mV, P<0.001). Impedances were stable in ALPs (334±68 to 329±52 Ω, P=0.17) and reduced in VLPs (789±351 to 646±190 Ω, P<0.001). Electrical measurements remained relatively stable from 1-6 months post-implant. No differences in electrical metrics were observed among ALP or VLP implant locations.

CONCLUSION

This first in-human evaluation of the new dual-chamber leadless pacemaker system demonstrated reliable electrical performance throughout the initial 6-month evaluation period.

Early real-world implant experience with a helix-fixation ventricular leadless pacemaker

BACKGROUND

Roughly one in six patients receiving conventional transvenous pacemaker systems experience significant complications within 1 year of implant, mainly due to the transvenous lead and subcutaneous pocket. A new helix-fixation single-chamber ventricular leadless pacemaker (LP) system capable of pre-deployment exploratory electrical mapping is commercially available. Such an LP may mitigate complications while streamlining the implantation. In this study, the initial real-world implant experience of the helix-fixation LP was evaluated following its commercial release.

METHODS

In patients indicated for single-chamber right ventricular pacing, helix-fixation Aveir VR LPs (Abbott, Abbott Park, IL) were implanted using the dedicated loading tool, introducer, and delivery catheter. Implant procedural characteristics, electrical parameters, and any 30-day procedure-related adverse events of consecutive implant attempts were retrospectively evaluated.

RESULTS

A total of 167 patients with Class I indication for permanent pacing received implants in four North American centers (57% male, 70 years old). Pre-fixation electrical mapping of potential sites allowed repositioning to be avoided in 95.7% of patients. Median [interquartile range] LP procedure and fluoroscopy durations were 25.5 min [20.0, 35.0] and 5.7 min [4.0, 9.2], respectively. Pacing capture threshold, sensed R-wave amplitude, and impedance were 0.8 V [0.5, 1.3], 9.0 mV [6.0, 12.0], and 705 Ω [550, 910], respectively. Implantation was successful in 98.8% of patients, with 98.2% free from acute adverse events.

CONCLUSIONS

The initial, real-world experience of the helix-fixation ventricular leadless pacemaker demonstrated safe and efficient implantation with minimal repositioning, viable electrical metrics, and limited acute complications.

Comparison of in-hospital outcomes and complications of leadless pacemaker and traditional transvenous pacemaker implantation

AIMS

Since their introduction in 1958, traditional cardiac pacemakers have undergone considerable upgrades over the years, but they continue to have a complication rate of ∼3.8%-12.4%. There are no randomized controlled trials comparing outcomes of leadless pacemakers (LPM) with single-chamber transvenous pacemakers (TV-VVI). The aim is to assess the differences in the procedural complications and in-hospital outcomes between LPM and TV-VVI implants.

METHODS AND RESULTS

We queried the national inpatient database from 2016 to 2019 to include adult patients undergoing LPM and TV-VVI. Admissions for leadless and single-lead transvenous pacemakers were identified by their appropriate ICD-10 codes. Complications were identified using ICD-10 codes that mostly represent initial encounter. The difference in outcomes was assessed using multivariable logistic regression and 1:1 propensity score matching between the two cohorts. Thirty-five thousand four hundred thirty expanded samples of admissions were retrieved of which 27 650 (78%) underwent TV-VVI with a mean age 81.3 ± 9.4 years and 7780 (22%) underwent LPM with a mean age of 77.1 ± 12.1 years. The LPM group had a higher likelihood of in-hospital mortality [adjusted odds ratio (aOR): 1.63, 95% CI (1.29-2.05), P < 0.001], vascular complications [aOR: 7.54, 95% CI (3.21-17.68), P < 0.001], venous thromboembolism [aOR: 3.67, 95% CI (2.68-5.02), P < 0.001], cardiac complications [aOR: 1.79, 95% CI (1.59-2.03), P < 0.001], device thrombus formation [aOR: 5.03, 95% CI (2.55-9.92), P < 0.001], and need for a blood transfusion [aOR: 1.54, 95% CI (1.14-2.07), P < 0.005]. The TV-VVI group had higher likelihood of in-hospital pulmonary complications [aOR:0.68, 95% CI (0.54-0.87), P < 0.002] and had a need for device revisions [aOR:0.42, 95% CI (0.23-0.76), P < 0.004].

CONCLUSION

There is a higher likelihood of all-cause in-hospital mortality and complications following LPM implantation in comparison to TV-VVI. This could be related to higher co-morbidities in the LPM group. Clinical trials aimed to accurately compare these two groups should be undertaken.