Dual-chamber leadless pacemaker implanted for first time in US
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The first pacemaker implantation was performed in 1958, and the technology has undergone many advances since then, the latest being a dual-chamber leadless system.
In February, Daniel J. Cantillon, MD, FACC, FHRS, research director and associate section head of cardiac electrophysiology and pacing in the Heart, Vascular & Thoracic Institute at Cleveland Clinic, performed the first implantation of a dual-chamber leadless pacemaker system (Aveir DR, Abbott) in the United States. The procedure was performed as part of the Aveir DR i2i single-arm study to evaluate the investigational system’s safety and efficacy.
Leadless pacemakers have lower mid- and long-term complication rates than transvenous pacemakers due to the absence of leads and surgical pockets, but they had only been single-chamber devices until now. According to press releases from Abbott and Cleveland Clinic, the dual-chamber system includes two leadless devices, one implanted in the right atrium and the other in the right ventricle, that communicate with each other beat-by-beat using Abbott’s i2i technology to regulate the heart synchronously between chambers.
Healio spoke with Cantillon, who is co-chair of the trial’s steering committee, about the needs the technology addresses, the patient populations that could benefit and the prospects of the trial.
Healio: Who is the appropriate patient population for the dual-chamber leadless pacemaker system?
Cantillon: These are patients with sinus node dysfunction and heart block. Anybody that would be getting a traditional dual-chamber pacemaker is eligible for this one.
Healio: How does this device differ from the current technology?
Cantillon: With the traditional transvenous pacemaker, there is a surgical pocket and incisional access; we stretch wires from the vein in the shoulder and we secure them into the heart muscle with very small screws. Studies show that by 3 years, up to one in six patients will have a problem with that system, which is most commonly related to either the pocket or the wires themselves. Complications include hematoma, infection, dislodgement of the wires, fracture of the wires and venous occlusive disease, which involves development of blood clots around the wires. The advantage of leadless cardiac pacing is that there are no wires, surgical pockets or incisional access. The devices are miniaturized and are delivered directly into the pumping chamber.
The single-chamber leadless pacemakers only serve about 10% of the population that needs pacing support. By having the dual-chamber pacemakers, where the two devices implanted in the heart can talk to each other and function cohesively, we are able to serve a much broader patient population.
Healio: What are some of the other potential benefits of this technology for patients?
Cantillon: When you compare the outcomes of single-chamber leadless cardiac pacemakers to single-chamber transvenous pacemakers, there is a significant advantage for the leadless devices in terms of midterm and long-term complications because there are no wires and pocket. We believe that the benefit of leadless pacing that exists over transvenous pacing can now be extended to the broader group of patients that need multichamber pacing.
Healio: Since the experience with this device is so new, what do you have to be cautious about during the first implantations?
Cantillon: The atrium, the upper chamber of the heart, is a thinner structure than the ventricle, which is the main pumping chamber in the lower part of the heart. The current FDA-approved leadless pacemakers go in the ventricle, which is thicker and more forgiving. Since the atrium is thinner, the design of the atrial leadless pacemaker had to be modified to accommodate that structure to avoid the risk for perforation or injury.
Another point is that the single-chamber leadless pacemaker does not have to communicate with other devices, but with the dual-chamber leadless pacemaker, it’s essential that the two devices communicate with each other using i2i communication. That is entirely new. Based on promising preclinical results, it was felt that the system was ready for a human investigational device exemption trial, and so far, we are off to a good start.
Healio: How was the first U.S. patient selected?
Cantillon: The first patient had a pacemaker that had been in place for many years and developed complications related to the transvenous wires, which had to be removed with laser tools, as we do for complications related to transvenous wires. The concern is that if you reimplant transvenous wires in a patient like that, the same type of issue will recur. So this technology was discussed with and offered to the patient because it could provide the same type of pacing support that had been needed for many years without the disadvantage of the wires. Therefore, this patient was a very solid candidate for this technology.
Healio: How did the procedure go?
Cantillon: It went great. Of course, we have to look at the results of the trial prospectively. There are a lot of enrollments and follow-up to be done. All over the world, we will enroll 550 patients for this trial, so we are just getting started.
Healio: What kinds of patients do you expect to enroll?
Cantillon: As reflected in the inclusion criteria, this trial is looking for a broad group of patients across the age spectrum, with different comorbidities. They just have to have a standard guidelines-based indication for dual-chamber pacing. We expect to see a good mix of patients that perhaps have higher-risk features such as complications from prior in-dwelling transvenous leads, like the patient from the first procedure, or patients that have never had a pacemaker previously and are simply seeking to prevent having complications, which unfortunately are not exactly uncommon.
Healio: Is there anything else you’d like to mention?
Cantillon: The retrievability piece is worth mentioning. We are often asked, since these miniaturized pacemakers are in the heart, how long will the battery last and what will we do when it needs to be replaced. We tell them that these devices, in contrast to the Micra single-chamber leadless pacemaker (Medtronic), were designed for retrievability. The single-chamber version of this system has been implanted since 2014. We have collected data on the chronic retrievals of those devices when the batteries become depleted. These data have been very encouraging. We are telling patients that we believe there will be an opportunity for us to retrieve these devices percutaneously and replace them. At Cleveland Clinic, there was a patient who had a single-chamber leadless device in the ventricle that was more than 7 years old. The battery had become depleted, and we were able to go in from the groin, retrieve the device and reimplant a new one with a fresh battery in the same procedure. We believe there is an opportunity to replace these devices percutaneously in both chambers; they were designed that way. Whether we will be able to do that, and what the success rates are, is going to be determined in follow-up. But our experience with the chronic retrievals of the devices implanted in the ventricle is promising. This gives us hope that retrieval of the new technology can be done in a minimally invasive fashion.
References:
- Abbott. abbott.mediaroom.com/2022-02-07-Abbott-Announces-Worlds-First-Implant-of-Dual-Chamber-Leadless-Pacemaker-in-Pivotal-Trial. Published Feb. 7, 2022. Accessed March 8, 2022.
- Cleveland Clinic. newsroom.clevelandclinic.org/2022/03/02/cleveland-clinic-performs-first-implant-of-a-dual-chamber-leadless-pacemaker-in-united-states/#:~:text=Cleveland%20Clinic%20has%20successfully%20implanted,invasive%20procedure%20with%20fewer%20complications. Published March 2, 2022. Accessed March 8, 2022.
- Clinicaltrials.gov. www.clinicaltrials.gov/ct2/show/NCT05252702. Published Feb. 23, 2022. Accessed March 8, 2022.
For more information:
Daniel J. Cantillon, MD, FACC, FHRS, can be reached at cantild@ccf.org.
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