Medical Design Briefs - July 2022 - 33

'Bionic' Pacemaker Reverses Heart Failure
The pacemaker
re-establishes the
heart's naturally
irregular beat.
University of Aukland
Aukland, New Zealand
A revolutionary pacemaker that
re-establishes the heart's naturally irregular
beat is set to be trialed in New
Zealand heart patients this year, following
successful animal trials.
" Currently, all pacemakers pace the
heart metronomically, which means a
very steady, even pace. But when you
record heart rate in a healthy individual,
you see it is constantly on the
move, " says Prof. Julian Paton, a lead
researcher and director of Manaaki
Manawa, the Centre for Heart Research
at the University of Auckland.
Manaaki Manawa has led the research
and the results have just been
published in leading journal Basic Research
in Cardiology.
" If you analyze the frequencies within
your heart rate, you find the heart
rate is coupled to your breathing. It
goes up on inspiration, and it goes
down on expiration, and that is a natural
phenomenon in all animals and
humans. And we're talking about very
ancient animals that were on the planet
430 million years ago. "
Twelve years ago, Paton was a member
of a group of scientists who decided
to investigate the function of this variability.
They made a mathematical
model that predicted it saved energy. That
made them question why a metronomic
heartbeat was used in heart-failure patients
who lacked energy. They asked, " Why aren't
we pacing them with this variability? "
All cardiovascular disease patients lose
the heart rate variability, which is an early
sign that something is going wrong.
" People with high blood pressure, people
with heart failure, their heart rate is
not being modulated by their breathing.
It may be a little bit, but it's very, very depressed,
very suppressed, " Paton says.
" We decided that we would put the
heart rate variability back into animals
with heart failure and see if it did anything
good, " says Paton.
Medical Design Briefs, July 2022
B
acclim.
1 week1 week
3-4 weeks 8-10 weeks
embolizations develop HF
C
90
70
0.1
-0.1
2 secs
E
120
Monotonically paced
100
0.1
Avg. HR 110 bpm
F
120 RSA paced
100
0.1
Avg. HR 107 bpm
Control animal
acclim. surgery recovery baseline
D
120
Heart failure
100
0.1
-0.1
2 secs
pacing off-pace
1-2 weeks 1 weeks 4 week1 week
A
Heart Rate (bpm)
RSA
RSA
Pacemaker
Diaphragmatic EMG (mv)
120
110
100
0.1
0.0
-0.1
Cardiac output
(L/min)
Blood pressure
(mmHg)
-0.1
-0.1
2 secs
2 secs
Schematic representation of the experimental setup. (Credit: Shanks, J., Abukar, Y., Lever, N.A. et al. Reverse
re-modeling chronic heart failure by reinstating heart rate variability. Basic Res Cardiol 117, 4, 2022)
Following positive signals in rats, the
latest published research was on a large
animal model of heart failure, performed
by Dr. Julia Shanks and Dr. Rohit
Ramchandra.
" And the big news is that we believe we
have now found a way to reverse heart
failure, " Dr. Ramchandra says.
Dr. Shanks, the research fellow who carried
out the research, explains, " There's
nothing really on the market that will cure
heart failure. All the drugs will do is make
you feel better. They don't address the issue
that you've got damaged tissue that's
not contracting as efficiently as it was.
" Our new pacemaker brings back
this variability, which of course is natuwww.medicaldesignbriefs.com
ral,
in a way you could call it 'nature's
pacemaker.' "
Dr. Ramchandra adds, " Currently,
pacemakers trigger a metronomically
steady beat, but this study shows introducing
a natural variation in the heartbeat
improves the heart's ability to pump
blood through the body. The other big
news is that we get a 20 percent improvement
in cardiac output, which is effectively
the ability of the heart to pump
blood through the body. And 20 percent
is a big number. "
" The pacemaker is almost like a bionic
device, " says Paton. " It understands
the signals from the body that tell the
device when we're breathing in and
33
DEMG (mv) HR (bpm)
DEMG (mv) HR (bpm)
DEMG (mv) HR (bpm)
DEMG (mv) HR (bpm)

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Medical Design Briefs - July 2022

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