Researchers at the University of Arizona have developed a battery-free light-powered pacemaker that uses optical stimulation of heart muscle cells to achieve heart rate. With conventional pacemakers, the leads of the device are attached to the wall of the heart using invasive hooks or screws. Small electric shocks are then sent throughout the heart and can potentially cause discomfort and pain. The new light-based pacemaker relies on four “chrome blades” that non-invasively wrap around the heart and use light to stimulate genetically modified cardiomyocytes to contract. The technology is primarily used in heart research in genetically modified animals, but it could also pave the way for less invasive pacemaker technology in humans.
Pacemakers are a huge success story for patients with atrial fibrillation and other types of arrhythmias. By delivering occasional electrical shocks to the heart, these devices help regulate heart rhythm. However, such technology can be uncomfortably invasive for patients. The electrical cables of these devices are hooked or screwed into the inner wall of the heart. In addition, when electrical impulses are sent to the heart, each cell receives the shock, often resulting in pain and discomfort.
“All the cells inside the heart are hit at once, 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 doesn’t even need a battery. The system is based on optogenetics, which usually involves genetically modified cells that respond to light. So far, this has only been achieved in experimental animals, with neurons being the most common cell type to target. In this case, the researchers are targeting heart muscle cells using light and can therefore stimulate them to contract without using an electric shock.
The technology consists of a wrap-around mesh containing four petals that can touch a large portion of the heart. The network contains a light source and recording electrodes that provide information about the heartbeat. So far, the researchers have shown that the device can work in a mouse strain that contains light-sensitive cells, but there may be scope for such technology in the clinic in the future.
“Since we have to shock the whole heart to do this now, these new devices can do much more precise targeting, which makes defibrillation both more effective and less painful,” said Igor Efimov, another researcher involved in the study. “This technology could make life easier for patients around the world while helping scientists and doctors learn more about how to monitor and treat the disease.”
Study in Scientific progress: Wireless, fully implantable pacing and recording with on-device calculation for closed-loop pacing and defibrillation
About: University of Arizona