Improved detection of atrial fibrillation could prevent disabling strokes
Improved detection of atrial fibrillation could prevent disabling strokes.
A clinical trial examining the efficacy
of two devices to monitor and detect atrial fibrillation (AF), or an irregular
heartbeat, in ischemic stroke patients — one an implantable device that
monitors over 12 months, the other an external device that monitors over a
30-day period — found the implantable device is more than three times more
effective in detecting AF, and both are a significant improvement over the
current standard of care in Alberta, Canada.
The Post-Embolic Rhythm Detection With Implantable Versus
External Monitoring (PER DIEM) study, led jointly by University of Alberta and
University of Calgary researchers, was published today in the journal JAMA. The findings are
expected to significantly change practice in how clinicians look for AF in Albertan
patients following ischemic stroke.
“We know that (the current method of monitoring) isn’t as
effective as it could be in picking up atrial fibrillation from this study
because regardless of which arm of the study patients went into, we were picking
up anywhere from five to 15 per cent extra atrial fibrillation,” said
Brian Buck, a stroke neurologist and associate professor of medicine at the U
of A. “We found in the study there were a lot of patients with undetected
atrial fibrillation, even after they received the standard cardiac
Atrial fibrillation causes about one in four strokes in Alberta.
Detecting it early is key to preventing further disabling strokes in patients
who have already experienced ischemic stroke, a type of stroke caused by a
blockage in an artery that supplies blood to the brain. If atrial fibrillation
is detected, clinicians have treatments — mainly blood thinners — that can
reduce the risk of stroke by almost 70 per cent.
The standard test in Alberta for AF is a 24-hour
electrocardiogram monitor. In the PER DIEM trial, 300 Albertan patients who had
suffered a stroke were randomized to one of two new devices that can monitor
for AF for longer durations. The study showed that the implantable device
picked up three times more new AF than the 30-day monitor (15 per cent versus
five per cent). All of the patients in the clinical trial with new AF were
started on blood thinners.
“We didn’t expect that we would get such a dramatic
increase with the longer recording, even though it intuitively makes
sense,” said study co-author Michael Hill, professor of neurology at the
University of Calgary and senior medical director for stroke with Alberta
Health Services’ Cardiovascular and Stroke Strategic Clinical Network. “Most
people suspected that detection rates apply to only certain subtypes of
ischemic stroke. This study showed that theory is not correct.”
“We believe that those patients that were identified with
atrial fibrillation are now, for the rest of their lives, going to have a much
lower risk of having a stroke in the future,” added Buck, who is also a
member of the U of A’s Neuroscience and Mental Health Institute.
One of the patients who took part in the trial was Norman Mayer,
the sitting mayor of the central Alberta community of Camrose for the past 32
years. Mayer recalls being admitted to the emergency department about five
years ago after not feeling well and experiencing sudden pain. After
examination, the clinicians on duty informed him that he had likely experienced
a minor stroke.
After being stabilized, Mayer was informed of the clinical trial
and given the option of participating. After giving his consent, he was
randomly assigned to the group of patients who were given the implantable
“It was the luck of the draw, and the advantage of it was
that it’s inconspicuous and wearing (an external device) would not have been
very appealing to me,” said Mayer. “So I had (the implantable device)
tucked into my chest. It’s there and nobody knows about it except for me and my
“It gives you a bit of a comfort level, I guess. It’s not
bothering you. It’s just there and a part of life,” he added. “It
gives you the feeling that if something was to go wrong, somebody’s going to be
in touch to let you know (what steps need to be taken).”
With better monitoring, clinicians may be able to diagnose much
more AF after stroke and dramatically reduce the risk of future disabling
stroke. According to the Canadian Coordinating Office for Health Technology
Assessment (CADTH), the external device costs about $1,000 per patient to
administer, while the implantable device typically costs over $5,000 per
patient. The implantable device had the added advantage of remote monitoring,
reducing the need for trips to the hospital — an important consideration for
rural Albertans. The team says an in-depth cost-benefit analysis is needed to
determine the best approach to providing superior care while also providing
savings for the health-care system.
“The biggest problem with stroke is that it dramatically
impacts people’s lives. So you take a healthy, independent person with a big
disabling stroke, and they often end up being dependent on others for help with
care. So that’s terrible for patients and it’s very expensive for the system.
If you can prevent even a few of those big disabling strokes per year, it helps
the person and reduces the burden on the health system,” said Buck.
“This new evidence will help guide selection of what
strategy is best going forward,” added Hill. “We need to go beyond
(24-hour monitoring) for Albertan patients. But if the system is going to pay
for this technology, we need to know more definitively that patients are going
to end up with lower stroke rates in the future.”
The researchers say studies to this point have shown a trend in
that direction, but more work is needed to prove it definitively. They hope to
address those questions in future research.
- Brian H. Buck, Michael D. Hill, F. Russell Quinn, Ken S. Butcher, Bijoy K. Menon, Sajad Gulamhusein, Muzaffar Siddiqui, Shelagh B. Coutts, Thomas Jeerakathil, Eric E. Smith, Khurshid Khan, Phillip A. Barber, Glen Jickling, Lucy Reyes, Supriya Save, Paige Fairall, Lori Piquette, Noreen Kamal, Derek S. Chew, Andrew M. Demchuk, Ashfaq Shuaib, Derek V. Exner. Effect of Implantable vs Prolonged External Electrocardiographic Monitoring on Atrial Fibrillation Detection in Patients With Ischemic Stroke. JAMA, 2021; 325 (21): 2160 DOI: 10.1001/jama.2021.6128