Wireless power could cut cord for patients with implanted heart pumps

July 13, 2011

Researchers envision a future where patients would install transmission coils in their homes and workplaces to create zones where the implant would receive uninterrupted power (credit: U of Washington)

Researchers at the University of Washington and the University of Pittsburgh Medical Center have tested a wireless power system for ventricular assist devices (mechanical pumps to give failing hearts a boost), or VADs.

VAD were originally developed as temporary measures for patients awaiting a heart transplant. But as the technology has improved, these ventricular assist devices commonly operate in patients for years.

The researchers devised an inductive system that adjusts the frequency and other parameters as the distance or orientation between the transmitter and receiver coils changes, allowing for flexible yet efficient wireless power over medium distances.

Using this wireless system means no power cord poking through the skin, dramatically reducing the risk of infection and improving the patient’s quality of life, the researcher said. They envision a vest that could hold an external transmitter coil connected to a power cord or battery.

A small receiver coil implanted under the patient’s skin would connect to a battery that holds enough power for about two hours, meaning the patient could be completely free for short periods of time. Longer term, the researchers imagine additional power transmitters placed under a patient’s bed or chair, allowing patients to sleep, work or exercise at home unencumbered.

They demonstrated that the system could power a commercial heart pump running underwater using a receiver coil as small as 4.3 cm (1.7 inches) across. The power transmitted reliably with an efficiency of about 80 percent.

The researchers presented the work in Washington, D.C. at the American Society for Artificial Internal Organs annual meeting, where it received the Willem Kolff/Donald B. Olsen Award for most promising research in the development of artificial hearts.