FEBRUARY 29 2020 LISTENER 19
is shorter than the girls’. “That’s one of
the most dangerous things about long
QT – you can have it and never have
symptoms,” she says.N
ow, scientists will learn more about
how the nerve and heart-muscle
cells interact to regulate heart
rate, using heart and nerve cells grown
from stem cells made from the blood
of patients, including the Maoates.
Auckland-based Swedish scientist Annika
Winbo, who is leading the research, says
international studies so far have focused
only on the heart and heart-muscle cells.
The local work, which last year won a
$144,000 Heart Foundation research
grant, is growing nerve and heart cells of
patients and healthy controls together
to study how the nerve cells regulate the
heart-muscle cells and whether one or
both are dysfunctional. “We can see if the
impulses from the nerve cells are normalTH
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and only the heart cells have an
abnormal reaction, or if there
is abnormal neurotransmission
going on,” she says.
Although studies overseas
have already found
abnormalities in
the heart-muscle
cells, Winbo’s work
suggests there are
also functional
differences in the
nerve cells – a
groundbreaking
finding. She is
also growing heart and
nerve cells from patients
and healthy controls
together to see if normal heart
rhythm can be “rescued” if one
or other comes from a person
without the condition. She says
if doctors better understand the
mechanisms involved, it could
improve risk management,
and potentially lead to new
therapies.
She and her colleague,
Professor Jon Skinner, a
specialist in children’s heart-
rhythm disturbances, are also
collaborating on a genetic study
of the mutations that cause
the condition in New Zealand.
They’ve found, for example, that
although mutations in Māori are rarer,
they also tend to be more severe. Winbo’s
interest in the condition was sparked
by the higher prevalence – about 1:500-
1:1000 – in northern Sweden, where she
was brought up. The chance to collaborate
on research with Skinner, who has a
“stellar” international reputation, brought
her down under.
“I’m really grateful that people
are getting excited about
wanting to learn about it,”
says Mandy Maoate of the
research, “because it’s been
under the radar for a long
time. Most people don’t
know about it and I’ve
lost three of my family to
sudden cardiac arrest.”
T
he family dare
to hope for the
“c-word” – a cure
- which would be
life-changing. Georgia and Teina take
portable defibrillators with them wherever
they go, and Georgia says the knowledge
that she could drop dead whenever she
swims is a constant worry. “It’s hard
being so different from
your peers, as well as all
the other things you have
to deal with as a teenager.”
For nearly a year after the
diagnosis, the sporty family
stopped all those activities
before realising that wasn’t
the way they wanted to
live. They then changed
their focus to risk reduction. The
older girls also take beta blocker
heart drugs, something Teina is
expected to be prescribed soon. It’s not
well understood how the beta blockers
work in long QT, although it’s possible
they affect both nerve and heart cells.
“A cure would be wonderful,” Georgia
says, “but also being able to be better
informed about how we can do the thingswe used to do pre-diagnosis, knowing that
we were a bit safer.”
“For us to never swim again is not an
option,” says Mandy, “so it’s about how
to make swimming safe.” She and her
husband, Riki, have told the girls not
to jump into cold ocean water from a
boat, for example, and to swim at the
beach only with their friends and the
defibrillator nearby.
But already, their interaction
with the doctors and the research
has had one unexpected outcome.
Georgia starts her first year as a
medical student this year, and
Ruby thinks she may follow
suit. “I’d always thought
medicine was something
I might like to do, but
it’s certainly cemented
it as a career,” says
Georgia.Long QT type 1 is the most
common identifiable
cause of death in youngpeople who have no
other abnormalities
found at autopsy.- From left, Georgia, Teina and Ruby
Maoate. 2. With their parents, Riki and
Mandy Maoate. 3. Georgia visits Ruby in
hospital after her implant operation.
Annika Winbo: seeing
if normal heart rhythm
can be “rescued”.An automated
external
defibrillator.3
2