In a groundbreaking advancement in medical technology, researchers at Northwestern University have unveiled the world's smallest pacemaker—a device so tiny it can be injected directly into the heart using a syringe. This innovative, wireless, and biodegradable pacemaker is designed to provide temporary cardiac pacing, particularly benefiting newborns with congenital heart defects.

Measuring just 1.8mm by 3.5mm, the pacemaker is smaller than a grain of rice. Its diminutive size allows for minimally invasive implantation, eliminating the need for traditional surgical procedures. Once its job is done, the device naturally dissolves within the body, removing the necessity for a second surgery to extract it.

"Our major motivation was children," said Igor Efimov, a cardiologist at Northwestern University who co-led the study. "About 1% of children are born with congenital heart defects. The good news is that these children only need temporary pacing after surgery. In about seven days or so, most patients' hearts will self-repair. But those seven days are absolutely critical."

The pacemaker operates in tandem with a soft, flexible, wearable patch placed on the patient's chest. This patch monitors the heart's rhythm and, upon detecting irregularities, emits pulses of near-infrared light. These light pulses penetrate the skin to activate the pacemaker, which then delivers electrical stimulation to regulate the heartbeat.

The device is powered by a galvanic cell mechanism that reacts with the body's natural fluids to generate electricity, eliminating the need for an external power source. 

This innovation addresses the risks associated with traditional temporary pacemakers, such as infection and internal bleeding caused by external wires. By providing a safer, less invasive option, it represents a significant leap forward in pediatric cardiac care.

The research team envisions broader applications for this technology, including adult cardiac care and other medical fields requiring temporary bioresorbable electronic devices.

For more detailed information, you can read the full study published in the journal Nature.