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Year : 2021  |  Volume : 3  |  Issue : 1  |  Page : 42-43

Atrioventricular synchrony with a leadless pacemaker

Illinois Masonic Medical Center, Chicago, IL, USA

Date of Submission16-Sep-2020
Date of Decision01-Dec-2020
Date of Acceptance16-Dec-2020
Date of Web Publication17-Feb-2021

Correspondence Address:
Marc R Iskandar
3134 N. Clark St., Chicago, IL 60657
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ACCJ.ACCJ_36_20

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Leadless pacemakers are more frequently used today. One of their latest advances is their ability to provide atrioventricular synchrony via a single-chamber device. Our aim is to give an example of the function of this type of pacemaker and the patients likely to benefit from it.

Keywords: Accelerometer, leadless, pacemaker

How to cite this article:
Iskandar MR, Brady PA. Atrioventricular synchrony with a leadless pacemaker. Ann Clin Cardiol 2021;3:42-3

How to cite this URL:
Iskandar MR, Brady PA. Atrioventricular synchrony with a leadless pacemaker. Ann Clin Cardiol [serial online] 2021 [cited 2021 Nov 27];3:42-3. Available from:

  Introduction Top

Leadless pacemakers are a recently available alternative to traditional pacemakers of single-chamber pacing capability that limits their utility to patients who require only ventricular pacing.[1] This <2 g device is impressively the size of a dime [Figure 1]d[2] and provides comparable ventricular pacing to a conventional pacemaker without the need for chest incision, pocket dissection or its associated risk of infection, hematoma, or erosion.[3] Whereas its first generation offered to solve ventricular sensing and pacing, the latest platform allows for atrial mechanical sensing broadening the pacing indications.
Figure 1: (a) Right anterior oblique view of Micra introducer at the inferior vena cava – right atrial junction with catheter tip in the right ventricle, (b) Left anterior oblique view of Micra catheter tip approximated to the intraventricular septum with contract injection to confirm apposition to the wall, (c) Delivered Micra pacing capsule attached to the right ventricular septum with freely deployed tines (3 of 4 visible), (d) Example of leadless pacemaker with fixation tines, (e and f) Demonstration of atrioventricular synchrony on electrocardiogram with single-chamber device

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  Case Report Top

A 72-year-old male with a history of hypertension, diabetes, end-stage renal disease on dialysis, and cellulitis presented to the hospital with new-onset weakness limiting his functional capacity to minimal walking. He is found to have complete heart block. After ruling out metabolic disturbance, exogenous overmedications among other reversible causes, we recommended pacemaker implantation. During consideration for the type of device, the patient's history including average atrial rate in the 60–80 beats per minute range, left-sided aortovenous shunt, and cellulitis was of particular concern with conventional transvenous pacing systems as they would affect the circulation as well as pose a risk for infection. After discussion with the patient, we proceeded to implant a leadless single-chamber pacing device with atrioventricular (AV) pacing ability.

  Discussion Top

By means of a femoral long introducer [Figure 1]a and [Figure 1]b, the device capsule is easily deployed [Figure 1]c and attached to the lower interventricular septum via 4 nitinol colloid tines.

This latest generation device utilizes automated enhanced accelerometer-based algorithms allowing it to distinguish cardiac cycle time intervals. Despite being a single-chamber device, this algorithm accounts for atrial systole and couples it to ventricular pacing, thereby enabling effective AV synchrony, as shown in [Figure 1]e and [Figure 1]f.

The AV synchrony unique to this device makes it suitable for paroxysmal or permanent high-grade AV block in the presence or absence of atrial fibrillation, especially when transvenous pacing systems are high risk such as in patients on dialysis, prone to infections, or with compromised upper chest circulation.[4] Their success rate is >99%, recovery time is immediate, and effectiveness is comparable to conventional devices. Post Micra bacteremia is extremely rare and even when diagnosed was proved to resolve with antibiotics.[5] In fact, several features of the leadless pacemakers render its low risk for infection including its size, location, and parylene coating of the device which limits organism ability to adhere to it.

  Conclusion Top

This novel ability for AV synchrony in leadless pacing systems represents a novel expansion of pacing indications and an alternative to a high-risk patient with infection risk or prone to upper circulatory access compromise. Leadless devices represent a fundamental change in the field of cardiac pacing since the earliest devices with fully dual-chamber capable devices expected in the not too distant future.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Reynolds D, Duray GZ, Omar R, Soejima K, Neuzil P, Zhang S, et al. A Leadless Intracardiac Transcatheter Pacing System. N Engl J Med 2016;374:533-41.  Back to cited text no. 1
2. [Internet] Minnesota: Walking, Inc. Medtronic gets European approval for smallest pacemaker. [Updated 2015 April 15; .Available from: [Last accessed on 2020 Dec 05].  Back to cited text no. 2
El-Chami MF, Al-Samadi F, Clementy N, Garweg C, Martinez-Sande JL, Piccini JP, et al. Updated performance of the Micra transcatheter pacemaker in the real-world setting: A comparison to the investigational study and a transvenous historical control. Heart Rhythm 2018;15:1800-7.  Back to cited text no. 3
Steinwender C, Khelae SK, Garweg C, Chan JYS, Ritter P, Johansen JB, et al. Atrioventricular Synchronous Pacing Using a Leadless Ventricular Pacemaker: Results From the MARVEL 2 Study. JACC Clin Electrophysiol 2020;6:94-106.  Back to cited text no. 4
El-Chami MF, Soejima K, Piccini JP, Reynolds D, Ritter P, Okabe T, et al. Incidence and outcomes of systemic infections in patients with leadless pacemakers: Data from the Micra IDE study. Pacing Clin Electrophysiol 2019;42:1105-10.  Back to cited text no. 5


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