“Wires literally protrude from the body, attached to a pacemaker outside the body,” according to Northwestern University professor of cardiology and biomedical engineering Igor Efimov. This brutal reality of conventional temporary pacemakers points out the dangers that come with them, ranging from infections to damage during removal. These complications, unfortunately, contributed to Neil Armstrong’s demise following a bypass operation. But with a breakthrough revolution a grain-of-rice-sized pacemaker a new morning breaks.
Temporary pacemakers are typically needed following heart surgery, particularly in children undergoing treatment for congenital heart defects. The devices calms heart rhythms through those precious periods of recovery, usually lasting around seven days. Traditional systems use wires snaking out of the chest that lead to external power sources. Removal of the wires can result in severe complications, such as blood loss and damage to tissue. Efimov mentions, “About 1% of children are born with congenital heart defects. The good news is that these children only need temporary pacing after a surgery. In about seven days or so, most patients’ hearts will self-repair. But those seven days are absolutely critical,”
The device that was developed by researchers at Northwestern University is an engineering wonder. It’s only 13.8 milligrams and measures 1.8 by 3.5 by 1 millimeter in dimensions, small enough to be inserted into the tip of a syringe. It can be inserted through a minimally invasive injection that only needs a less than 3 mm cut in the skin. Efimov calls it “without precedent” in size. In contrast to the 2021 quarter-sized pacemaker, this pacemaker does away with the requirement of an external antenna since it creates electrical currents using electrodes touching bodily fluids. Not only does it facilitate miniaturization to an even greater extent, but wires and outside power sources are also done away with.
Perhaps the most surprising aspect of the device is that it is biodegradable. The pacemaker melts and disintegrates once it has functioned, eliminating the necessity for surgical removal. The invention eliminates the possibility of complications from device removal, including scarring of tissues and injury to heart muscles. Northwestern’s bioelectronics pioneer John Rogers illustrates, “By minimizing the size, we dramatically simplify the implantation procedures, we reduce trauma and risk to the patient, and, with the dissolvable nature of the device, we eliminate any need for secondary surgical extraction procedures.”
The pacemaker is combined with a patch that a patient wears on his chest. This soft, pliable device picks up irregular heart rhythms and sends bursts of near-infrared radiation to remotely activate the pacemaker. Infrared radiation, known to be capable of passing through tissue and skin, is used to stimulate the pacemaker to excite the heart at a frequency of choice. “Infrared light penetrates very well through the body,” Efimov said. “If you put a flashlight against your palm, you will see the light glow through the other side of your hand. It turns out that our bodies are great conductors of light.”
The technology has been applied in a broad model set, ranging from mice and rats to dogs and pigs, and even human hearts taken from organ donors. Banting-sized, it provides full-sized stimulation. Actually, scientists see implanting arrays of such tiny pacemakers across the heart so that sophisticated, coordinated stimulation of other areas can be achieved. Such an approach would restore normal heart rhythm more effectively and enable coupling the pacemaker with other medical implants, like heart-valve replacements.
Beyond cardiac uses, the applications potential is vast. Efimov proposes using it as electrical stimulators in bone and nerve growth, wound healing, and pain control. Rogers concludes, “Because it’s so small, the pacemaker can be integrated with almost any kind of implantable device.”
The implications of this technology are larger than its immediate medical applications. It is MRI-compatible, a huge advance over earlier pacemakers that made noisy images because they had metallic components. Also, their magnesium and zinc components are both biocompatible and biodegradable to the body.
Although it has not yet reached human trials, no one can dispute the possibility the technology holds. Efimov and Rogers believe it will become a reality someday, with further development underway to further refine the device and introduce it to clinics. As of Efimov’s recent remarks, “Now, we can place this tiny pacemaker on a child’s heart and stimulate it with a soft, gentle, wearable device. And no additional surgery is necessary to remove it.”
This breakthrough pacemaker is a quintessential illustration of the intersection of medical need and engineering know-how, promising safer, more successful treatment for patients of all ages. Its possibility of revolutionizing temporary cardiac pacing and branching off into fields outside the heart is testament to the revolutionizing potential of medical innovation.
