A wireless pacemaker designed by Prof. Aydin Babakhani of Rice University can be implanted directly into a patient's heart.
Researchers from the university, along with colleagues from the Texas Heart Institute (THI), are presenting a prototype of the device during IEEE's International Microwave Symposium (IMS) in Honolulu, June 4 to 9. The device harvests energy wirelessly from radio frequency radiation transmitted by an external battery pack.
Traditionally, pacemakers are located away from the heart and transmit electrical signals via wires or “leads” to prompt the heart to keep a steady beat. Surgeons can periodically replace their onboard batteries with minor surgery. But complications related to the leads, including bleeding and infection, are common problems. The new device, which is a microchip, does away with leads altogether. And while other lead-less pacemakers have been introduced, their form factors limit them to a single heart chamber. The microchip can be implanted directly to pace multiple points inside or outside the heart.
Adjustments to the power transmitted to the receiving antenna controls pacing signal frequency. A test on a pig demonstrated that the device could tune the animal’s heart rate from 100 to 172 beats per minute.
Less than 4 millimeters wide, the chip incorporates a receiving antenna, AC-to-DC rectifier, power management unit and pacing activation signal; a capacitor and switch join the chip on a circuit board smaller than a dime. The chip receives power from 8 to 10 gigahertz microwaves.
"This technology brings into sharp focus the remarkable possibility of achieving the 'Triple Crown' of treatment of both the most common and most lethal cardiac arrhythmias: external powering, wireless pacing and – far and away most importantly – cardiac defibrillation that is not only painless, but is actually imperceptible to the patient," said Dr. Mehdi Razavi, director of clinical arrhythmia research and innovation at THI, who collaborated with Babakhani on development and testing.
According to Babakhani, the invention has prompted new collaborations among the Texas Medical Center institutions as well as the University of California at San Diego.