World-first transient pacemaker dissolves in the body after use

June 29, 2021

US scientists from Northwestern University and George Washington University have developed a new type of temporary pacemaker that will not require surgical removal. The fully-implantable, battery-free device can be used in patients who need temporary pacing after cardiac surgery or while waiting for a permanent pacemaker; this eliminates even the need for wires/leads, which may introduce infections or damage delicate tissue(s).

The new device is fully biocompatible and weighs less than half a gram. At only 250 microns thick, it can easily be implanted onto the heart where a set of integrated electrodes emit an electrical pulse, wirelessly drawing on energy from an external antenna. All components of the implant can be naturally absorbed into the body’s biofluids over five to seven weeks.

Surgeons currently sew on temporary pacemaker electrodes on the heart muscle during open heart surgery. These have leads that exit the front of a patient’s chest, and connect to an external pacing box that delivers a current to control the heart’s rhythm – potential complications of implanted temporary pacemakers, although uncommon, include infection, dislodgement, torn or damaged tissues, bleeding and blood clots.

“Instead of using wires that can get infected and dislodged, we can implant this leadless biocompatible pacemaker,” says Dr. Rishi Arora, a cardiologist at Northwestern Medicine.

“The circuitry is implanted directly on the surface of the heart, and we can activate it remotely. Over a period of weeks, this new type of pacemaker ‘dissolves’ or degrades on its own, thereby avoiding the need for physical removal of the pacemaker electrodes. This is potentially a major victory for post-operative patients.”

The device has so far been effective when tested out on the hearts of mice, rats, rabbits and canines, along with human models, capable of pacing hearts of differing sizes. Interestingly, the rate at which it dissolves can be controlled by the composition and thickness of the bioresorbable materials, allowing the team to dictate the exact number of days the pacemaker remains functional for.

“Hardware placed in or near the heart creates risks for infection and other complications,” says Northwestern’s John A. Rogers, who led the device’s development. “Our wireless, transient pacemakers overcome key disadvantages of traditional temporary devices by eliminating the need for percutaneous leads for surgical extraction procedures – thereby offering the potential for reduced costs and improved outcomes in patient care. This unusual type of device could represent the future of temporary pacing technology.”