Tiny Light-Powered Pacemaker

Engineers in the US have made a groundbreaking development in the field of medical technology by creating a pacemaker small enough to be injected into the body. This innovative pacemaker, developed at Northwestern University, is specifically designed for newborn babies with congenital heart defects, whose hearts are tiny and fragile.

Measuring at a mere 3.5 x 1.8mm and 1mm thick, the device is smaller than a single grain of rice, yet its battery structure is capable of delivering the same level of stimulation as a full-sized pacemaker. To control the pacing of the heart, the pacemaker is paired with a small, soft, flexible, wireless wearable device that attaches to the patient’s chest. When an irregular heartbeat is detected, the wearable device emits an infrared pulse to activate the pacemaker, which then controls the pacing through short pulses penetrating the patient’s skin, breastbone, and muscles.

This revolutionary pacemaker is designed for patients who require temporary pacing and is engineered to dissolve naturally in the body once it is no longer needed. By adjusting the composition and thickness of the materials used in the device, the team can precisely control the number of days before the pacemaker dissolves, eliminating the need for surgical extraction.

Prof John Rogers, the leader of the device development, expressed the significance of this advancement, stating, “We have developed what is, to our knowledge, the world’s smallest pacemaker. There’s a crucial need for temporary pacemakers in the context of pediatric heart surgeries, and that’s a use case where size miniaturization is incredibly important. In terms of the device load on the body — the smaller, the better.”

Northwestern experimental cardiologist Igor Efimov, who co-led the study, emphasized the impact on children, saying, “About 1% of children are born with congenital heart defects, and these children often require temporary pacing after surgery. With this tiny pacemaker, we can stimulate a child’s heart gently and effectively without the need for additional surgery for removal, which is critical during the post-operative period.”

Building on their previous work, the team developed a dissolvable pacemaker in 2021 powered by near field communications (NFC). The new pacemaker utilizes a light-based scheme for wireless control, allowing for a significant reduction in size compared to its predecessor. By using two different metals in a galvanic cell as electrodes, the pacemaker can deliver electrical pulses to the heart when in contact with biofluids, forming a battery through chemical reactions.

With the ability to integrate multiple small pacemakers across a larger heart, each responsive to different wavelengths of infrared light, the potential for more sophisticated synchronization and tailored pacing strategies is vast. This advancement opens up possibilities for enhanced care and treatment options for patients with various heart conditions, showcasing the transformative impact of miniaturized, dissolvable pacemakers in the field of cardiology.