On 2 April 2025, engineers at Northwestern University published a study on a new dissolvable pacemaker, smaller than a grain of rice and powered by light. This device, which can be implanted nonsurgically using a syringe, has the potential to save the lives of newborns with heart problems and may also assist adults with certain heart defects.
The need for temporary pacemakers
Every year, about 1% of infants are born with heart defects, many of which only need a temporary pacemaker for about seven days to allow the heart to heal naturally. However, in areas with limited medical resources, what should be a simple procedure can lead to serious complications. Current methods for temporary pacemakers in adults involve surgeons attaching electrodes directly to the heart and connecting them to an external device with wires. After the electrodes are no longer needed, they are removed, but this can lead to risks such as infections, tissue damage, and blood clots. Sometimes, the wires can become trapped in scar tissue, causing further issues. Igor Efimov, an experimental cardiologist and co-leader of the study, noted that astronaut Neil Armstrong died in 2012 after experiencing internal bleeding related to a temporary pacemaker.
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Previous innovations in pacemaker technology
In 2021, a team from Northwestern University, including Efimov, introduced a temporary pacemaker that could dissolve in the body and did not need large batteries or wires. This device works similarly to smartphones and radio-frequency identification tags, which are small chips used in electronic payments and tracking items. However, the pacemaker has a built-in antenna to send signals. When it detects an irregular heartbeat, it uses light to turn on and control the heart’s pacing. This light can easily pass through the skin and muscles.
The original pacemaker worked well but was limited in size due to its antenna. The researchers then focused on making the pacemaker even smaller. They replaced the radio antenna with a design that uses light for communication and changed the power source to a galvanic cell, a type of battery that generates electricity from chemical reactions in the body. The new pacemaker has two metal electrodes that create an electrical current when they come into contact with body fluids. This current stimulates the heart through a tiny switch activated by infrared light.
The final design of the pacemaker is 1.8mm wide, 3.5mm long, and only 1mm thick. It can provide the same electrical stimulation as a standard pacemaker. Because the materials used in this pacemaker dissolve over time, there is no need for a follow-up surgery to remove it, which reduces the risk of complications.
Future possibilities
The researchers believe that future advancements could allow for multiple pacemakers to be used together in the heart, enabling more complex treatments for conditions such as arrhythmias, which are irregular heartbeats. They also see potential for integrating these pacemakers into other medical devices such as heart valve replacements, which can cause heart block (a condition where the heart’s electrical signals are disrupted). The small size of the pacemaker means it could also be used in other medical tools for pain relief and nerve or bone repair. Ultimately, the team’s main goal is to help children. Efimov emphasised that this tiny pacemaker can be placed on a child’s heart and gently stimulate it, providing a safer and more effective solution for young patients.
