A Bioresorbable Pacemaker for Temporary Cardiac Pacing

Cardiac pacing is needed on a temporary basis in many clinical scenarios. One common scenario is immediately after cardiac surgery. It is standard practice to place temporary epicardial ventricular pacing wires on the heart after cardiac surgery. These are externalized and connected to a battery-powered temporary pacing system. Ventricular wires can be used to provide pacing to prevent bradycardia post operatively in the event that the patient develops transient heart block or sinus node dysfunction. Atrial wires can also be placed and used to pace-terminate post-operative atrial flutter, or allow for AV sequential pacing. These wires are removed prior to discharge from the hospital by pulling them out, or by cutting them at the level of the skin to avoid complications related to complete extraction.

Temporary transvenous pacing is used when patients develop severe bradycardia refractory to standard resuscitation efforts. These temporary pacing wires are often placed in the emergency department when patients present with complete AV block and are hemodynamically unstable, or in hospitalized patients who develop profound bradycardia or asystole. Patients undergoing percutaneous heart valve procedures, such as transcatheter aortic valve replacement (TAVR), can at times develop heart block of unpredictable duration and need temporary pacing after the procedure. Patients who are pacemaker dependent and undergo pacemaker lead extraction for infection need temporary pacing while awaiting reimplantation.

There is a need for a better temporary pacing system for all of these situations. New research describes a fully bioresorbable, leadless, battery-free cardiac pacemaker.¹ This report describes the outcome of a multicenter collaborative effort that further developed previous work on bioresorbable devices pioneered by Professor John Rogers, now at Northwestern University in the Department of Biomedical Engineering. The Rogers team developed a bioresorbable nerve stimulator² and had partnered during past efforts with Professor Igor Efimov in the Department of Biomedical Engineering at George Washington University to demonstrate proof of concept of a fully resorbable cardiac pacing system.³ In this most recent paper, both groups collaborated with Dr. Rishi Arora’s experimental large animal lab at the Feinberg School of Medicine, Northwestern University. Using an open-chest canine model, they were able to attach a bioresorbable electrode connected to a bioresorbable power-receiving coil directly to the heart. Power was delivered from an external transmission coil to the bioresorbable receiving coil and successfully captured the ventricle. Power could be delivered effectively at distances that would be needed clinically if the pacemaker were to be placed on the epicardium and the transmission coil was worn on the chest wall. They demonstrated that these bioresorbable devices can provide battery-free means for pacing hearts of various sizes with tailored geometries and timescales for operation and bioresorption.¹

There is a growing need for temporary epicardial and transvenous cardiac pacing. A fully bioresorbable, leadless, battery-free cardiac pacemaker has the potential to be used for a limited amount of time as an alternative to temporary epicardial pacing after cardiac surgery. A transvenous version, either with a transvenous lead or leadless, could serve as a temporary endocardial pacing option when heart block occurs at the time of TAVR or for patients who are currently unable to have a permanent system implanted due to ongoing infection or other short-term contraindication. If these systems prove to be reliable, they might also allow for patients to be discharged home while awaiting a more permanent pacing solution. 

Stay safe,

Bradley P. Knight, MD, FACC, FHRS

@DrBradleyKnight
Editor-in-Chief, EP Lab Digest

Disclosures: Dr. Knight reports that he is a consultant, speaker, investigator, and offers fellowship support for Abbott, Baylis Medical, Biosense Webster, Inc., BIOTRONIK, Boston Scientific, Medtronic, and SentreHEART. He has received compensation for serving as a consultant to CVRx, Inc.

1. Pfenniger A, Koo J, Johnson DA, et al. A bioresorbable, leadless pacemaker - is it time? Heart Rhythm. 2020;17_Suppl:D-MP06-03. https://doi.org/10.1016/j.hrthm.2020.04.013
2. Choi YS, Hsueh YY, Koo J, et al. Stretchable, dynamic covalent polymers for soft, long-lived bioresorbable electronic stimulators designed to facilitate neuromuscular regeneration. Nat Commun. 2020;11:5990. doi: 10.1038/s41467-020-19660-6
3. Gutruf P, Yin RT, Lee KB, et al. Wireless, battery-free, fully implantable multimodal and multisite pacemakers for applications in small animal models. Nat Commun. 2019;10:5742. doi: 10.1038/s41467-019-13637-w