ESC Congress 2017 In Review – Focus on Arrhythmias - 13

ESC Congress 2017

In Review

Arrhythmias

Acute or early delayed cardioversion AF patients may
be pretreated with either intravenous or oral AADs.
Pretreatment with AADs is believed to increase the likelihood of restoration of sinus rhythm and helps prevent
recurrent AF although this is not supported by available
systematic data. Post-treatment AADs may improve
maintenance of sinus rhythm, but studies are not definitive due to potential confounding.
Anticoagulation therapy in acute cardioversion may
reduce the risk of thromboembolic events in patients with
stroke risk factors (heart failure, hypertension, diabetes,
prior stroke, female sex, or age above 65 to 75 years)
[Airaksinen KJ et al. J Atr Fibrillation. 2013]. However,
this therapy is normally not required in low-risk patients.
In elective cardioversion, although the data is not clear, it
may be beneficial. Selection of the type of cardioversion
(acute vs elective; pharmacological vs electrical; early vs
delayed) is subject to various factors and may influence
acute and long-term success rates.
Francisco Marín, MD, Department of Cardiology,
Hospital Universitario Virgen de la Arrixaca, Murcia, Spain,
discussed how to deal with left atrial appendage (LAA)
clots when performing nonvalvular AF, which occurs in
between 0.5% to 14% of patients. Patients with LA thrombus are at an increased risk for embolic stroke or death
(Figure 2) [Bernhardt P et al. Am J Cardiol. 2004].
Figure 2. Thrombus Persistence Over 12-Months

Thrombus Persistency

1.0

0.8

0.6

0.4

0.2

0
0

100

150

200

250

300

350

400

cases with anticoagulation. Age, LAA hypocontractility
and left ventricular ejection fraction were found to be
independently associated with the occurrence of LAA
thrombus [Da Costa A et al. Am Heart J. 2017].
Michael D. Ezekowitz, MBChB, DPhil, MA, Sidney
Kimmel Medical School, Thomas Jefferson University,
Lankenau and Bryn Mawr hospitals, Philadelphia, PA,
USA, spoke about cardioversion in the modern era. The
availability of NOACs which have a rapid onset of action,
(hours) is changing medical practice. Post hoc analyses
of cardioversions in all the pivotal trials that lead to
the approval of the NOACs found low event rates; for
example the first and largest, the RE-LY study, showed
that dabigatran is a reasonable alternative to warfarin
in cardioversion patients with or without TOE guidance
[Nagarakanti R et al. Circulation. 2011].
In Dr Ezekowitz's opinion, a limitation with RE-LY,
and similar studies, is that study subjects were on
prolonged periods of anticoagulation therapy prior to
cardioversion. An objective of prospective cardioversion clinical trials comparing NOACs and VKAs was to
expedite cardioversion and evaluate their efficacy in
preventing strokes and systemic embolisms while maintaining an acceptable level of bleeding. These trials
suffer from the limitation of being underpowered; low
events rates due to effective anticoagulation require
a trial size of between 25,000 to 45,000 patients to
be adequately powered, which are not feasible, so the
studies is generally underpowered. Three recent cardioversion trials (EMANATE, X-VeRt and ENSURE-AF) have
similar designs, baseline demographics, outcomes, and
endpoints. Results from all 3 show that NOACs are an
effective and safe alternative to treatment for patients
undergoing electrical cardioversion for nonvalvular
AF and they may allow cardioversion to be performed
promptly following the start of anticoagulation. The primary outcome from EMANATE is shown in Figure 3.
Figure 3. EMANATE: Stroke/Systemic Embolic Outcomes

Reprinted from Bernhardt P et al. Fate of left atrial thrombi in patients with
atrial fibrillation determined by transesophageal echocardiography and
cerebral magnetic resonance imaging. Am J Cardiol. 2004;doi: 10.1016/J.AMJCARD.2004.06.010. Reproduced with permission from Excerpta Medica.

ESC Guidelines [Kirchhof P et al. Europace. 2016] recommend performing a TOE prior to cardioversion and
anticoagulation when a thrombus is detected, with subsequent delay of cardioversion for 3 to 4 weeks. A follow-up TOE is warranted. Anticoagulation is associated
with thrombus resolution in > 80% of patients [Collins
LJ et al. Circulation. 1995; Jaber WA et al. Am Heart J.
2000]. In a recently published study, prevalence of TOE-
detected LAA thrombus was similar with NOACs and
VKAs and thrombus resolution was obtained in 50% of

Proportion of Patients
with Stroke/SE

Time (Days)
Apixaban (events: 0/753)
Heparin/VKA (events: 6/747)
* 5 ischaemic, 1 haemorrhagic stroke with 0 SE events

0.020
0.015
0.010
0.005
0

P = .0164
0

Time to Stroke/SE (days)

VKA, vitamin K antagonist; SE, systemic embolism.
Reproduced with permission from MD Ezekowitz, , MBChB, DPhil, MA.

All the speakers agreed that the use of anti-coagulants,
preferably NOACs is necessary in patients undergoing cardioversion, to resolve the risks associated with
thrombus and possible stroke.

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