Surgeries to replace heart pacemaker batteries could one day be a thing of the past. A team of researchers at the University of Michigan have designed a device the powers cardiac pacemakers from heartbeat vibrations.

The device gathers energy from these vibrations and transforms it to electricity. The electrical signals are then transmitted to the heart to keep it beating in a healthy rhythm and to power an implanted defibrillator or pacemaker. Currently, the only way to replace batteries, which last 5-10 years, involves repeated surgeries.

The study entitled “Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters,” is published in the current print edition of Applied Physics Letters.

Amin Karami, a research follow in the U-M Department of Aerospace Engineering, explained:

“The idea is to use ambient vibrations that are typically wasted and convert them to electrical energy. If you put your hand on top of your heart, you can feel these vibrations all over your torso.”

Although the team have not yet built a prototype, they have created detailed blueprints and conducted simulations showing that the idea would work. According to the researchers, heartbeat vibrations would essentially be caught by a thin (hundredth-of-an-inch) slice of a special “piezoelectric” ceramic material. In response to being caught the vibrations would briefly expand. Piezoelectric material’s convert mechanical stress (which causes them to expand) into an electric voltage.

The ceramic layer has been precisely engineered by Karami and his colleague Daniel Inman, chair of Aerospace Engineering at U-M, to a shape that can gather vibrations over a wide rage of frequencies. In addition, the team added magnets as their additional force field can significantly increase the electrical signal produced by the vibrations.

According to Karami, these mini-medical devices could produce 10 microwatts of power, approximately 8 fold the amount needed to operate a pacemaker. The researchers highlight that the device always produces more energy than the pacemaker needs, and performs well below and above the normal heart rate range (7 to 700 beats per minute).

The team originally designed the device for light unmanned airplanes in order to generate power from wing vibrations.

The National Institute of Standards and Technology and the Institute for Critical Technology and Applied Science at Virginia Tech, funded the study.

Written by Grace Rattue