Medical Design Briefs - December 2022 - 24

Battery-Free, Light-Powered Pacemaker May Improve
Quality of Life for Heart Disease Patients
The pacemaker uses
precise targeting
capabilities to bypass pain
receptors and reduce
patient discomfort.
University of Arizona
Tucson, AZ
Atrial fibrillation - a form of irregular
heartbeat, or arrhythmia - leads to
more than 454,000 hospitalizations and
nearly 160,000 deaths in the United
States each year. Globally, it is estimated
that approximately 60 million people
are affected by the condition.
Pacemakers are lifesaving devices
that regulate the heartbeats of people
with chronic heart diseases like atrial
fibrillation and other forms of arrhythmia.
However, pacemaker implantation
is an invasive procedure, and the lifesaving
pacing that the devices provide
can be extremely painful. Additionally,
pacemakers can only be used to treat a
few specific types of disease.
In a paper published in Science Advances,
a University of Arizona-led team
of researchers detail the workings of a
wireless, battery-free pacemaker they
designed that could be implanted with
a less-invasive procedure than currently
possible and would cause patients less
pain. The study was helmed by researchers
in the Gutruf Lab, led by biomedical
engineering assistant professor
and Craig M. Berge Faculty Fellow
Philipp Gutruf.
Currently available pacemakers work
by implanting one or two leads, or points
of contact, into the heart with hooks or
screws. If the sensors on these leads detect
a dangerous irregularity, they send
an electrical shock through the heart to
reset the beat.
" All of the cells inside the heart get hit
at one time, including the pain receptors,
and that's what makes pacing or defibrillation
painful, " Gutruf says. " It affects
the heart muscle as a whole. "
The device Gutruf's team has developed,
which has not yet been tested in
humans, would allow pacemakers to
send much more targeted signals using
24
An artist's rendering shows how a new pacemaker, designed by a UArizona-led team of researchers, is
able to envelop the heart. The wireless, battery-free pacemaker could be implanted with a less-invasive
procedure than currently possible and would cause patients less pain. (Credit: Philipp Gutruf)
a new digitally manufactured mesh design
that encompasses the entire heart.
The device uses light and a technique
called optogenetics.
Optogenetics modifies cells, usually
neurons, sensitive to light, then uses
light to affect the behavior of those
cells. This technique only targets cardiomyocytes,
the cells of the muscle
that trigger contraction and make up
the beat of the heart. This precision will
not only reduce pain for pacemaker patients
by bypassing the heart's pain receptors,
but it will also allow the pacemaker
to respond to different kinds of
irregularities in more appropriate ways.
For example, during atrial fibrillation,
the upper and lower chambers of the
heart beat asynchronously, and a pacemaker's
role is to get the two parts back
in line.
" Whereas right now, we have to shock
the whole heart to do this, these new devices
can do much more precise targeting,
making defibrillation both more effective
and less painful, " says Igor
Efimov, professor of biomedical engineering
and medicine at Northwestern
University, where the devices were lab
tested. " This technology could make life
easier for patients all over the world,
while also helping scientists and physicians
learn more about how to monitor
and treat the disease. "
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The device uses light and a technique called optogenetics,
which modifies cells that are sensitive
to light, then uses light to affect the behavior
of those cells. (Credit: Philipp Gutruf)
n Flexible Mesh Encompasses
the Heart
To ensure that the light signals can
reach many different parts of the heart,
the team created a design that involves encompassing
the organ, rather than implanting
leads that provide limited points
of contact. The new pacemaker model
consists of four petal-like structures made
of thin, flexible film, which contain light
sources and a recording electrode. The
petals, specially designed to accommodate
the way the heart changes shape as it beats,
fold up around the sides of the organ to
envelop it, like a flower closing up at night.
Medical Design Briefs, December 2022

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Medical Design Briefs - December 2022

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