Life cycle management of Micra transcatheter pacing system: Data from a high-volume center

Second Micra leadless pacemaker implantation by using intracardiac echocardiography

The strategy after battery depletion was not established in Micra leadless pacemaker system (Micra). There are still some concerns in the 2nd Micra implantation, such as the mechanical interaction between both devices. The position of the 2nd Micra should be placed apart from the 1st Micra. We present a case of 1st Micra battery depletion who successfully underwent the 2nd Micra implantation under the intracardiac echo guidance. In our case, intracardiac echo was a very effective tool for confirming the location of Micra implantation.

Percutaneous extraction of a Micra AV transcatheter pacing system due to a rare sudden battery failure after 19 months from implantation: A first experience worldwide

INTRODUCTION

Micra AV Transcatheter Pacing System (TPS) represents an innovative second-generation leadless pacemaker which represents an effective alternative to conventional devices in selected cases. Intrinsic malfunctions of these devices are rare, requiring sometimes their retrieval. When performed in experienced centers, this procedure is safe.

CASE PRESENTATION

We describe a case of sudden battery malfunction of a Micra AV TPS, which required the extraction and the placement of a new pacing system in the right ventricle.

DISCUSSION

This case, which has never been reported, highlights the need to a careful fluoroscopic evaluation and the usefulness of remote monitoring.

The Micra Transcatheter Pacing System: past, present and the future

Leadless permanent pacemakers represent an important innovation in cardiac device developments. Although transvenous permanent pacemakers have become indispensable in managing bradyarrhythmia and saving numerous lives, the use of transvenous systems comes with notable risks tied to intravascular leads and subcutaneous pockets. This drawback has spurred the creation of leadless cardiac pacemakers. Within this analysis, we compile existing clinical literature and proceed to evaluate the efficacy and safety of the Micra Transcatheter Pacing System. We also delve into the protocols for addressing a malfunctioning or end-of-life Micra as well as device extraction. Lastly, we explore prospects in this domain, such as the emergence of entirely leadless cardiac resynchronization therapy-defibrillator devices.

Leadless Cardiac Pacing: New Horizons

Since the introduction of transvenous cardiac pacing leads, pacemaker system design has remained similar for several decades. Progressive miniaturisation of electronic circuitry and batteries has enabled a smaller, single pacing unit comprising the intracardiac electrodes, generator and computer. This review explores the development of leadless pacing, the clinical trials comparing leadless to transvenous pacing in addition to the future developments of multi-chamber leadless pacing.

Leadless Pacemakers: State of the Art and Selection of the Ideal Candidate

The field of cardiac pacing has been defined by constant development to provide efficacious, safe, and reliable therapy. Traditional pacing utilizes transvenous leads, which dwell in the venous system and place patients at risk for complications, including pneumothorax, bleeding, infection, vascular obstruction, and valvular compromise. Leadless pacemakers have been developed to overcome many of the challenges of transvenous pacing while providing safe and effective pacing therapy for an increasing population of patients. The Medtronic Micra transcatheter pacing system was approved by the FDA in April of 2016 and the Abbott Aveir pacemaker was approved in April of 2022. Several additional leadless pacemakers are in various stages of development and testing. There exists limited guidance on the selection of the ideal candidate for leadless pacemakers. Advantages of leadless pacemakers include decreased infection risk, overcoming limited vascular access, and avoidance of interaction with the tricuspid valve apparatus. Disadvantages of leadless pacemakers include right ventricular-only pacing, unclear lifecycle management, cost, perforation risk, and lack of integration with defibrillator systems. This review aims to provide an overview of the current state of the art of leadless pacemakers, currently approved systems, clinical trials and real-world evidence, considerations for patient selection, and future directions of this promising technology.

Leadless Pacing: Where We Currently Stand and What the Future Holds

PURPOSE OF REVIEW

Leadless pacemakers (LPs) are emerging as alternative cardiac implantable devices for the treatment of bradyarrhythmia. This article aims to review the data behind the safety and efficacy of these devices while highlighting their pros and cons.

RECENT FINDINGS

Prospective non-randomized studies and registries have found that LPs are associated with lower rate of device-related complications mainly driven by lower need for lead-related interventions as compared to traditional pacemakers. On the other hand, cardiac perforation appears to occur more frequently with LPs. LPs are associated with lower rate of device-related complications as compared to the traditional pacemakers. However, the rate of pericardial effusion is higher and is more severe. As we transition to multi-chamber LPs, it is important to ensure the safety and efficacy of these devices.

Performance of transcatheter pacing system use in relation to patients' age

PURPOSE

Real-world safety data on the use of transcatheter pacing systems particularly in very elderly patients is still limited. The aim of this analysis was to investigate the effect of age on the safety and efficacy of leadless pacemaker implant.

METHODS

From May 2016 through July 2019, 577 patients were implanted with a leadless single-chamber pacemaker according to current pacing indication in 15 Italian cardiologic centers. The population was divided into age quartiles for evaluation, including (1) < 70 years, (2) 70-77 years, (3) 78-83 years, and (4) ≥ 83 years. Procedural data, complications, and electrical parameters were collected at baseline and during the follow-up.

RESULTS

Procedural-related complication occurrence was very low (< 1.0%) and similar in the four subgroups according to age even if the older patients were more frail. No cardiac tamponade was reported. Among the groups, no difference was observed in procedural time, fluoroscopy time duration, and electrical parameters (mean pacing impedance: 750 ± 192 and 599 ± 156, mean pacing threshold: 0.7 ± 0.5 and 0.7 ± 0.6, and mean right ventricular sensing 10.7 ± 6.1 and 11.5 ± 4.8 at implant and last follow-up, respectively).

CONCLUSIONS

The reported data demonstrated a high degree of safety during leadless implant across all patient ages. Procedural complications and device electrical measurements were similar among the different ages.

Leadless atrio-ventricular synchronous pacing in an outpatient setting - early lessons learned on factors affecting atrio-ventricular synchrony

BACKGROUND

Leadless pacemakers (PMs) capable of atrio-ventricular (AV) synchronous pacing have recently been introduced. Initial feasibility studies were promising, but limited to just a few minutes of AV synchronous pacing. Real-world long-term data on AV synchrony and programming adjustments affecting AV synchrony in outpatients are lacking.

OBJECTIVE

To investigate AV synchrony and influences of PM programming adjustments in outpatients with leadless VDD PMs.

METHODS

All patients who received a leadless VDD PM (Micra™ AV, Medtronic, US) between 07/2020 and 05/2021 at our center were included in this observational study. AV synchrony was assessed repeatedly postoperatively and during follow-up using Holter ECG recordings. AV synchrony was defined as a QRS complex preceded by a p-wave within 300ms. The impact of programming changes during follow-up on AV synchrony was studied.

RESULTS

816 hours of Holter ECG from 20 outpatients were analyzed. During predominantly paced episodes (≥80% ventricular pacing), median AV synchrony was 91% (IQR 34-100%) when patients had sinus rates 50-80/min. Median AV synchrony was lower when patients had sinus rates >80/min (33%, IQR 29-46%, p<0.001). During a stepwise optimization protocol, AV synchrony could be improved (p<0.038). Multivariate analysis showed that a shorter maximum A3 window end (p<0.001), a lower A3 threshold (p=0.046), and minimum A4 threshold (p<0.001) improved AV synchrony.

CONCLUSION

Successful VDD pacing in the outpatient setting during higher sinus rates is more difficult to achieve than can be presumed based on the initial feasibility studies. The devices often require multiple reprogramming to maximize AV sequential pacing.