SUNDAY, Nov. 4 (HealthDay News) -- Implantable pacemakers have
been around for more than 50 years, but they've always had one
drawback: batteries that need to be replaced. Now, there are early
signs that a device that gains power from the patient's own
heartbeat might change all that.
The "energy harvester" device uses magnets plus vibrations from
within the chest cavity to create energy sufficient to power a
pacemaker, its developers report.
Right now, replacing a worn-out pacemaker battery requires
surgery that must happen about every seven years. That means that
"if the patient starts with a pacemaker at age 2, which is not
uncommon, then we are talking about 10 ... surgeries throughout
their life," noted co-researcher David Inman, chair of the
department of aerospace engineering at the University of Michigan,
in Ann Arbor.
So, the advent of a battery-free pacemaker "would be a huge
savings in terms of either reducing the number of operations, or
completely eliminating them," he said. "It would also be a huge
saving in terms of medical costs."
Details on the research are set to be presented Sunday at the
annual meeting of the American Heart Association in Los
According to Inman, the energy-harvesting device is the
brainchild of co-researcher M. Amin Karami, a postdoctoral
researcher working with Inman at the university. The tiny device is
about half the size of a conventional pacemaker battery and
utilizes piezoelectricity -- an electrical charge that's generated
from motion -- plus a small magnetic field.
"These two effects together take the natural vibrations inside the chest cavity, which are caused by the heart beating, and change it into electricity which then runs the pacemaker," Inman explained.
He stressed that the research remains at an early stage.
Estimates of the power available to the device once implanted in a
patient are based on 20-year-old data on the vibratory energy
inside the human chest, as well as newer data on energy generated
by pig and goat hearts.
According to Inman, the next step is to obtain up-to-date
measurements of heartbeat energy from patients undergoing heart
surgeries. Inman expects those measurements to be carried out
within the next four to five months.
After that, he said, "one of the major medical device
manufacturers has to say 'OK, we want to make this a product.'" The
prototype harvester he and Karami developed has worked as
predicted, generating more than 10 times the amount of energy
required to run a pacemaker, he added.
Another expert said the device shows promise, but there are
still questions about how it operates in the ling run.
"The advent of a self-charging pacemaker would be revolutionary," agreed Dr. Neil Sanghvi, an electrophysiologist at Lenox Hill Hospital in New York City.
He noted that while the risks involved in replacing a
pacemaker's battery are "typically low," in about 1 percent of
cases post-replacement infection occurs, often requiring surgical
removal of the pacemaker and long hospital stays. "A renewable
self-contained source of energy for pacemaker function would allow
us to prevent these rare but serious complications," Sanghvi
He also cited "several concerns," however. Since the harvester
relies on magnets, it would require "thorough testing to confirm
that outside sources of electromagnetic interference do not result
in device malfunction," according to Sanghvi. Most importantly,
"the technology needs to demonstrate reliable and persistent power
generation over years of use without seeing a significant decline
in power generation," he said.
Karami and Inman said that common appliances such as cellphones
or microwave ovens should not affect the energy harvester's
performance. And they added that it is possible the technology
might also be able to power other cardiac devices, such as
Still, Inman cautioned that all of that is years away, and much
more work needs to be done -- including testing self-powered
pacemakers in animals and then humans.
But the response from the medical community has been
encouraging, he said. "We wrote this little academic article in
Biophysics Letters[on the device]," he said, "and the phones
started ringing off the hook."
Experts note that findings presented at medical meetings are
typically considered preliminary until published in a peer-reviewed
Find out more about pacemakers at the
U.S. National Heart, Lung, and Blood
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