Researchers at the University of Arizona have developed a battery-free light-powered pacemaker that uses optogenetic stimulation of cardiomyocytes to achieve heart pacing. With conventional pacemakers, the leads of the device are anchored into the wall of the heart, using invasive hooks or screws. Small electrical shocks are then sent through the entire heart, potentially causing discomfort and pain. The new light-based pacemaker relies on four “petals” that wrap around the heart non-invasively, and uses light to stimulate genetically-modified cardiomyocytes to contract. The technology is primarily useful for cardiac research in genetically-modified animals, but it may also pave the way for less invasive pacemaker technologies in human patients.
Pacemakers are a huge success story for patients with atrial fibrillation and other types of arrythmias. By providing occasional electrical shocks to the heart, these devices help to regulate the heartbeat. However, such technology can be unpleasantly invasive for patients. The electrical leads of these devices are hooked or screwed into the interior wall of the heart. Moreover, when electrical signals are sent to the heart, every cell receives the shock, often leading to pain and discomfort.
“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,” said Philipp Gutruf, a researcher involved in the study. “It affects the heart muscle as a whole.”
To address this, the University of Arizona team developed a new type of pacemaker, one that does not even require a battery. The system is based on optogenetics, which typically involves genetically modified cells that are light-responsive. To date, this has only been achieved in experimental animals, where neurons are the most commonly targeted cell type. In this instance, the researchers are targeting cardiomyocytes using light, and can therefore stimulate them to contract without using an electric shock.
The technology consists of a wrap-around mesh that includes four petals that can contact a large portion of the heart. The mesh features sources of light and recording electrodes that provide information on the heartbeat. So far, the researchers have shown that the device can work in a strain of mouse that contains light-sensitive cells, but there may be scope for such technologies in the clinic in the future.
“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, another researcher involved in the study. “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.”
Study in Science Advances: Wireless, fully implantable cardiac stimulation and recording with on-device computation for closed-loop pacing and defibrillation