Around one percent of babies are born with congenital heart defects. Many of them require only about seven days of temporary cardiac support after surgery, while the heart heals itself. What they don't need is what conventional pacemakers have always required: wires protruding through the skin, attached to an external device, to be surgically removed once they've done their job. That removal has always carried a serious risk. Scar tissue can envelop the wires, and pulling them free can tear healthy heart muscle. Neil Armstrong — who survived the Moon landing — died from internal bleeding caused by exactly this complication.
A team at Northwestern University in Evanston, Illinois, led by biomedical engineer Igor Efimov and bioelectronics pioneer John Rogers, set out to eliminate the problem entirely. The result is what they believe to be the world's smallest pacemaker: smaller than a grain of rice, just 1mm thick, 1.8mm wide and 3.5mm long, it can be injected into the body through a syringe tip — no open surgery required.
Control comes from outside the body entirely. A soft, flexible patch worn on the chest continuously monitors the heart's rhythm. When it detects an irregularity, it emits near-infrared light — the kind that passes through skin and bone — which activates the pacemaker and restores normal rhythm. No wires. No external device. No removal procedure. The pacemaker simply dissolves when it's no longer needed, absorbed safely by the body over the course of one to three years.
The research was published in the journal Nature and tested successfully in animal models and donor hearts. Human clinical use still requires regulatory approval, but the researchers have already begun exploring further applications — in heart valves, nerve restoration, and beyond.