This wireless, battery-free pacemaker is a real game changer for heart disease patients

A pacemaker is a small, battery-operated device implanted in the chest to regulate the heartbeats of people with heart diseases like atrial fibrillation, a form of irregular heartbeat.

According to the Centers for Disease Control and Prevention, the condition — arrhythmia — leads to 54,000 hospitalizations and contributes to about 158,000 deaths each year. Though pacemakers are lifesavers for many people, their implantation is invasive surgery, and the pacing that the devices provide can be uncomfortable and painful.

"All of the cells inside the heart get hit at one time, including the pain receptors, and that's what makes pacing or defibrillation painful," Philipp Gutruf, biomedical engineering assistant professor at the University of Arizona, said in a statement. "It affects the heart muscle as a whole."

Current pacemakers require one or two points of contact into the heart with hooks and screws. According to the release, 'if the sensors on these leads detect a dangerous irregularity, they send an electrical shock through the heart to reset the beat.'

To counter the problems, Gutruf and a team of researchers designed a wireless, battery-free pacemaker that can be implanted in a less invasive procedure and would cause patients less pain. The design encompasses the heart instead of implanting leads that serve limited points of contact.

Their findings are published in Science Advances.

The model contains petal-like structures that can envelop the heart

The developed device permits pacemakers to send more targeted signals using a new digitally manufactured mesh design that covers the entire heart. It employs a technique called optogenetics which can reduce pain for pacemaker patients by "bypassing the heart's pain receptors." It will also let the pacemaker respond to various irregularities in better ways.

The researchers cite an example: During atrial fibrillation, the upper and lower chambers of the heart do not beat in tandem, and the pacemaker's role is to get them to beat synchronously.

"Whereas right now, we have to shock the whole heart to do this, these new devices can do much more precise targeting, making defibrillation both more effective and less painful," said Igor Efimov, professor of biomedical engineering and medicine at Northwestern University, where the devices were lab-tested. "This technology could make life easier for patients all over the world, while also helping scientists and physicians learn more about how to monitor and treat the disease."

The new model, which has not been tested in humans, comprises four petal-like structures made of thin, flexible film, which contain light sources and a recording electrode. Interestingly, the petals accommodate the heart as it changes shape to beat and even fold up around the sides of the organ protecting it.

The new pacemaker uses light to 'affect' the heart

"Current pacemakers record basically a simple threshold, and they will tell you, 'This is going into arrhythmia, now shock,'" Gutruf said. "But this device has a computer on board where you can input different algorithms that allow you to pace in a more sophisticated way. It's made for research."

Instead of electrical signals, the new pacemaker uses light to affect the heart. This lets it continue recording information when the pacemaker has to defibrillate. This isn't refined in current pacemakers, as an electrical signal from the defibrillation can hinder recording, which can give an "incomplete" picture of cardiac episodes.

The device doesn't require a battery, thereby saving pacemaker patients from replacing the battery in their device every five to seven years.

The current model was a success in animal models. Once work is expanded, the pacemaker could be a real lifesaver for millions.

Study Abstract:

Monitoring and control of cardiac function are critical for investigation of cardiovascular pathophysiology and developing life-saving therapies. However, chronic stimulation of the heart in freely moving small animal subjects, which offer a variety of genotypes and phenotypes, is currently difficult. Specifically, real-time control of cardiac function with high spatial and temporal resolution is currently not possible. Here, we introduce a wireless battery-free device with on-board computation for real-time cardiac control with multisite stimulation enabling optogenetic modulation of the entire rodent heart. Seamless integration of the biointerface with the heart is enabled by machine learning–guided design of ultrathin arrays. Long-term pacing, recording, and on-board computation are demonstrated in freely moving animals. This device class enables new heart failure models and offers a platform to test real-time therapeutic paradigms over chronic time scales by providing means to control cardiac function continuously over the lifetime of the subject.