Leadless pacemakers marked a significant advancement in cardiac care, primarily because traditional pacemakers are dependent on leads, which are prone to breakage over time. Currently, two FDA-approved leadless pacemakers are available, both of which are delivered via the femoral vein and placed inside the right side of the heart. These leadless devices are positioned on the heart’s interior, but their implantation can result in perforation, and there’s the theoretical risk that they could shift out of place, potentially moving to the lungs—a dangerous scenario. For adult patients, the procedure to implant a pacemaker is typically minimally invasive, allowing them to return home on the same day. However, this approach is not feasible for many children, either due to their smaller veins or pre-existing heart conditions such as a shunt or hole in the heart. As a result, children needing a pacemaker often undergo open-chest surgery, a major procedure that involves a hospital stay of several days. While leadless pacemakers are less invasive, concerns remain regarding the challenges of device removal and the large sheath size required for insertion in young patients. Researchers have now developed a groundbreaking prototype for a new leadless pacemaker designed for both children and adults.

The innovative micropacemaker, developed by researchers at Children’s National Hospital (Washington, D.C., USA), in partnership with engineers at (University of Southern California, USC, Los Angeles, CA, USA), is designed to be the first fully leadless system implanted in the pericardial space surrounding the heart. This new approach would allow the pacemaker to be implanted in a minimally invasive manner in children and those with congenital heart disease, while offering a safer leadless pacemaker option for adults. In their proof-of-concept study, published in Heart Rhythm, the researchers demonstrated how this novel pacemaker would work, its potential benefits for both children and adults, and the next steps in its development. This new device would be the first pacemaker to remain entirely outside the heart, with no leads, and instead of being placed inside the heart, it would be positioned on the heart's exterior. This design not only reduces the risk for both adults and children but also addresses challenges faced in patients with congenital heart conditions.

The innovative design offers several key advantages, with the most significant being the elimination of the pacing lead, which is a primary cause of pacemaker failure. By positioning the entire system outside the heart, the device avoids entering the bloodstream, further reducing risk. The most important benefit, however, is that the pacemaker can be implanted in a minimally invasive way, avoiding the need for major surgery even in small patients. This new pacemaker system would be implanted percutaneously, with a needle inserted into the pericardial space—the sac surrounding the heart. Once the needle is in place, the surgeon advances a wire to deliver the pacemaker into the space through a thin sheath, resembling a straw. This method avoids the veins and the heart's interior, ensuring minimal surgery. The system would be safer than current leadless pacemakers and would offer the benefits of leadless pacing to a much broader patient population. Researchers believe that this pericardial leadless design could eventually become the preferred pacing option for nearly all patients requiring a pacemaker.

In addition to eliminating the risk of perforation, this new pacemaker design also avoids the need for placement in the right ventricle, making it possible to pace the left ventricle instead. This positioning is ideal for optimizing the heart's cardiac squeeze. Furthermore, the design allows for the implantation of multiple devices, enabling dual-chamber pacing by adding one in the atrium, or even biventricular pacing, also known as cardiac resynchronization therapy, by placing one in the other ventricle. These innovations are why researchers believe this device could represent the future of pacemakers. The researchers achieved a major breakthrough after introducing two wire-loop rings that extend out from the device once it is deployed. These rings are designed to prevent the pacemaker from shifting or rolling out of place. The device is designed with a shape and size similar to current leadless pacemakers, ensuring its compatibility with the advanced technologies already in use in pacemakers. The team is now actively seeking an industry partner to assist in the development of the device, with plans to move forward with human trials.

“We specifically designed our system to have a similar shape and size to current leadless devices,” said Yaniv Bar-Cohen, MDYaniv Bar-Cohen, MD, Director of Electrophysiology in the Heart Institute at Children’s Hospital Los Angeles. “We believe our system would be safer than today’s leadless pacemakers while expanding the option of leadless pacing to a much larger number of adults.” 

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