Practice Update: Cardiology

7 / 32

patients had a prior history of stroke or
transient ischemic attack. The endpoint
was device-detected AF for ≥5 minutes.
AF was detected at a rate of 34.4% per
year, with a mean time from ILR insertion to
detection of 5.1±5.5 months. Subclinical or
device-detected AF occurred before clin-
ical diagnosis of the arrhythmia in 69% of
the patients at a median of 82.5 days ear-
lier. In patients with a history of a cerebral
ischemic event, AF detection rates were
higher at 39.4% per year.
Among secondary endpoints, 4 patients
had an ischemic stroke during follow-up, of
whom none had detected AF. One hemor-
rhagic stroke developed in a patient with
detected AF who was started on anticoag-
ulation. Of the 90 patients with AF, 60 were
started on anticoagulation, in 45 of whom
the decision was made from the device-de-
tected arrhythmia.
This study has several important clinical
findings. First, the data continue to support
the use of long-termmonitors for AF detec-
tion in patients with a cryptogenic stroke.
The average time required to detect (>5
months) highlights the utility of long-term
implantable monitors compared with ambu-
latory monitors. Current studies such as
Apixaban for Treatment of Embolic Stroke
of Undetermined Source (ATTICUS) and
Rivaroxaban Versus Aspirin in Second-
ary Prevention of Stroke and Prevention
of Systemic Embolism in Patients With
Recent Embolic Stroke of Undetermined
Source (NAVIGATE ESUS) will evaluate if
empiric anticoagulation, given the very
high expected rates of subclinical AF in
cryptogenic stroke patients, will lower sec-
ondary stroke rates.
Second, this study demonstrates the value
of ILRs in higher-risk patients for AF with
a yield of arrhythmia detection in approx-
imately 1 in 3. What remains to be known
is if this early detection can lead to tar-
geted therapies that will significantly impact
outcomes compared with conventional
approaches based on clinical AF diagnosis.
Third, this study highlights the lack of sen-
sitivity in AF diagnosis based upon patient
symptoms and routine clinical investigation.
Finally, this study continues to prompt the
question, is AF a marker of a systemic vas-
cular disease state or a focal risk factor of
the atrium? The answer to this question is
critical as we consider pill-in-the-pocket
anticoagulation, left atrial appendage
closure devices, and rhythm control
approaches to lower stroke risk. If AF is a
focal disease of the left atrium, then these
approaches should lower stroke risk. How-
ever, if AF is a risk marker of severity of a
systemic disease state, then anticoagula-
tion strategies will be needed long-term
and stroke risk reduction will be depend-
ent on treatment and modification of the
processes driving the systemic disease. In
this study of patients at higher risk for AF
with ILRs, the few strokes that did occur
were independent of AF. In consideration
of these data in addition to other data from
CIED trials that show lack of consistent tem-
poral correlation between AF incidence
and stroke,5,6 we must question the tra-
ditional hypothesis of the role of AF and
stroke, and, as a consequence, how we
will reduce stroke events in the future.
References
1. Chugh SS, Havmoeller R, Narayanan K, et al.
Worldwide epidemiology of atrial fibrillation: a
Global Burden of Disease 2010 Study. Circulation
2014;129(8):837-847.
2. Brunner KJ, Bunch TJ, Mullin CM, et al. Clinical
predictors of risk for atrial fibrillation: implications
for diagnosis and monitoring. Mayo Clin Proc
2014;89(11):1498-1505.
3. Sanna T, Diener HC, Passman RSet al.
Cryptogenic stroke and underlying atrial
fibrillation. N Eng J Med 2014;370(26):2478-2486.
4. Healey JS, Alings M, Ha AC, et al. Subclinical
Atrial Fibrillation in Older Patients [published
online August 4, 2017]. Circulation doi: 10.1161/
CIRCULATIONAHA.117.028845. [Epub ahead of
print]
5. Brambatti M, Connolly SJ, Gold MR, et al.
Temporal relationship between subclinical
atrial fibrillation and embolic events. Circulation
2014;129(21):2094-2099.
6. Martin DT, Bersohn MM, Waldo AL, et
al. Randomized trial of atrial arrhythmia
monitoring to guide anticoagulation in patients
with implanted defibrillator and cardiac
resynchronization devices. Eur Heart J
2015;36(26):1660-1668.
Dr Bunch is Medical Director
of Electrophysiology for
Intermountain Healthcare,
Intermountain Heart Institute,
Intermountain Medical
Center, Murray, Utah.
EDITOR’S PICKS 7
VOL. 2 • NO. 2 • 2017
Terms & conditions of entry: Entries are open to Australian residents (excluding the ACT) who are practising medical professionals. Only one entry per person will be accepted.
Entrants must complete the survey by answering all questions and submitting the completed survey online via the link provided by 23.59 (AEST) 30th September 2017 to be
eligible for the prize draw. There will be 1 (one) prize drawn on 30th September 2017 for a FitBit Alta HR worth $249 (recommended RRP). The winner will be notified by telephone
and email on the same day. For full terms and conditions, go to . NSW Permit No. LTPM/17/01510.
Important privacy notice: Elsevier Australia and its related bodies corporate recognise the importance of protecting your personal information in
accordance with the Privacy Amendment (Private Sector) Act 2000. For our full privacy statement visit
Take our survey to win
You may have noticed our new and improved look with more
• expert opinions • research articles • conference coverage
All content guided by PracticeUpdate’s internationally
recognised Advisory & Editorial Board.
We did it with you, the reader, in mind. Did we get it right or
have we simply lost the plot?
Have your say. Simply go to
or scan the QR code below to complete our 4-minute reader’s
survey to stand a chance to WIN a FitBit Alta HR worth $249!*
*Recommended RRP. Terms and conditions apply.