|Year : 2021 | Volume
| Issue : 1 | Page : 42-43
Atrioventricular synchrony with a leadless pacemaker
Marc R Iskandar
, Peter A Brady
Illinois Masonic Medical Center, Chicago, IL, USA
|Date of Submission||16-Sep-2020|
|Date of Decision||01-Dec-2020|
|Date of Acceptance||16-Dec-2020|
|Date of Web Publication||17-Feb-2021|
Marc R Iskandar
3134 N. Clark St., Chicago, IL 60657
Source of Support: None, Conflict of Interest: None
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
| Introduction|| |
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. This <2 g device is impressively the size of a dime [Figure 1]d 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. 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|| |
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|| |
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. 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. 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|| |
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.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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