Experimental Pacemakers Powered by the Heart's Own Motion

A new experimental device may be able to use converted energy from a patient’s heart to generate enough electricity to fully power a pacemaker.

Research presented at the American Heart Association 2012 Scientific Sessions, in Los Angeles, California, demonstrated the technical feasibility of using a piezoelectric energy-harvesting device to power a pacemaker, potentially showing the way to a batteryless future for implantable cardiac devices.

Current models of cardiac Implanted Electrical Devices (CIED) such as cardiac pacemakers and implantable cardioverter defibrillators are powered by batteries, and must be surgically removed every 5 to 10 years when the battery voltage is depleted. However, lead study author M. Amin Karami, PhD, of the Department of Aerospace Engineering at the University of Michigan in Ann Arbor, presented study results showing it is possible to use electrical charges generated by a patient’s heart’s beating motion (piezoelectricity) to power the devices. This finding suggests that the device would eliminate the need to replace the batteries of pacemakers.

“This approach is a promising technological solution for pacemakers, because they require only small amounts of power to operate,” said Karami.

The study tested an energy harvesting device that uses piezoelectricity, an electrical charge that is generated by motion. Traditional pacemakers can be powered either by linear or nonlinear piezoelectric energy harvesters. The linear devices only work effectively when a patient has a certain heart beat, so if the heart rate alters drastically, the device might be prevented from harvesting sufficient power to run the pacemaker.

Nonlinear piezoelectric harvesters (NPH) of the type used in this study convert ambient vibrations to electrical energy and from vibrations in the chest can produce power greater than the 1 microwatt required for CIED function.

While traditional harvesters capture vibrations in a narrow frequency range, NPH incorporate magnets can be optimized for complex and specific frequency content. The magnets are also used to enhance the power production and make the NPH less sensitive to changes in heart rate.

“Devices such as cell phones or microwave ovens would not affect the nonlinear device,” Karami said.

The nonlinear harvester used in the study generated sufficient power from heart rates of 20-600 beats per minute to power a pacemaker. Karami said that development of this technology promises to decrease size and increase longevity and functionality of CIEDs.

This study was co-authored by David Bradley, MD, Associate Professor of Pediatrics at the University of Michigan, Ann Arbor, and Daniel Inman, PhD, of the University of Michigan Aerospace Engineering department.