Heartbeats Might Power Cardiac Pacemakers

Piezoelectricity generated by the beating heart could one day power a pacemaker or even an implantable cardiac defibrillator (ICD), according to a new study.

Researchers at the University of Michigan (Ann Arbor, USA) have developed an experimental nonlinear energy harvester that uses piezoelectricity generated from a beating heart to provide enough electricity to power a pacemaker, thus eliminating the need for replacements when batteries are spent. According to the researchers, the novel approach is a promising technological solution for pacemakers, because they require only small amounts of power to operate.

The investigational device is about half the size of batteries now used in pacemakers, and includes a self-powering back-up capacitor. To develop the device, the researchers first measured heartbeat-induced vibrations in the chest; they then used a vibrator to reproduce the movements in the laboratory, connecting it to the prototype cardiac energy harvester. Measurements of the prototype's performance, based on a wide range of simulated heartbeats, showed the energy harvester generated more than 10 times the power required by modern pacemakers. The study was presented at the annual meeting of the American Heart Association (AHA), held during November 2012 in Los Angeles (CA, USA).

“What we have proven is that under optimal conditions, this concept is working,” said lead author and study presenter M. Amin Karami, PhD, of the department of aerospace engineering. “Many of the patients are children who live with pacemakers for many years. You can imagine how many operations they are spared if this new technology is implemented.”

Two types of energy harvesters can power a typical pacemaker: linear and nonlinear. Linear harvesters work well only at a specific heart rate, so heart rate changes prevent them from harvesting enough power. In contrast, a nonlinear harvester (like that used in the study) uses magnets to enhance power production and is less sensitive to heart rate changes. According to the researchers, devices such as cell phones or microwave ovens would not affect the nonlinear device.

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