ESC Congress 2017 In Review – Focus on Arrhythmias - 4

Main Session

Evolving Treatments for Atrial
Fibrillation
Written by Maria Vinall

Ablation of AF-Where Do We Stand?
Atrial fibrillation (AF) is the most common arrhythmia;
it can be treated by either antiarrhythmic drug therapy
(AAD) or catheter ablation and pulmonary vein isolation
(PVI). Karl-Heinz Kuck, MD, Asklepios Klinik St. Georg,
Hamburg, Germany, believes that mortality and ischaemic stroke outcomes after catheter ablation are better
than after AAD. The Swedish health registries support
his opinion with recent data showing annualised mortality rates of 0.77% and 1.62% (P < .001) for ablated and
nonablated patients, respectively (Figure 1). Annualised
stroke rates were also significantly (P = .013) lower,
0.70% for ablated and 1.01% in nonablated patients
[Friberg L et al. Eur Heart J. 2016]. However, randomised
clinical trials supporting this hypothesis are so far still
missing, especially regarding stroke prevention.
Figure 1. Impact of Catheter Ablation on Mortality: Data From
Swedish Health Registries

Incidence of Ischaemic Stroke
in Relation to AF Ablation

10%

Catheter ablation
No catheter ablation

P < .013
0
0

Ablation 2496
No ablation 2496

1049
1059

668
681

Years

At Risk
2457
2396

2126
2049

1840
1782

1434
1403

338
366

Reprinted from Friberg L et al. Catheter ablation for atrial fibrillation is associated with lower incidence of stroke and death: data from Swedish health
registries. Eur Heart J. 2016. doi:10.1093/eurheartj/ehw087. By permission of
Oxford University Press on behalf of the European Society of Cardiology.

AF is generally considered to progress from paroxysmal through persistent to 'permanent' forms, as
a result of atrial electrical and structural remodelling.
This process can be interrupted with early and more
active approaches to AF detection followed by rhythmreversion, and maintenance of sinus rhythm (SR), Prof
Kuck believes [Nattel S et al. Eur Heart J. 2014]. The pulmonary veins (PV) have been identified as a primary initiating source of AF [Haissaguerre M et al. N Engl J Med.
1998]. The ESC Guidelines for AF ablation [Kirchhof P
et al. Eur Heart J. 2016] state that the cornerstone for a
successful procedure is to target PVs and/or PV antrum

October 2017

for electrical isolation. Circumferential PVI results in
stable SR in a large proportion of patients for up to 5 years
[Ouyang F et al. Circulation. 2010] and freedom from
atrial tachyarrhythmias for up to 10 years [Heeger CH
et al. Circ Arrhythm Electrophysiol. 2018. In press].
There are 2 approaches to PVI: radiofrequency catheter using heat in a focal point by point delivery guided by
electroanatomical mapping and the cryoballoon approach
using freezing inside a balloon with single step delivery,
guided by fluoroscopy without mapping. Although efficacy
outcomes are similar between the 2 approaches, the cryoballoon offers some advantages according to Prof Kuck:
shorter procedure times, fewer serious adverse events,
fewer cardiovascular rehospitalisations, lower rate of
repeated ablations, and overall lower cost [Kuck KH et al.
N Engl J Med. 2016; Chun JRK et al. J Am Heart Assoc.
2017].
Patients with persistent AF may need more than one
ablation procedure [Tilz RR et al. J Am Coll Cardiol. 2012].
Past strategies included other approaches such as PVI
plus linear lesions, PVI plus ablation of complex fractionated atrial electrograms (CFAE), or a combination of PVI
plus linear lesions plus CFAE ablation. However, no reduction in the rate of recurrent AF has been demonstrated
with PVI plus CFAE or PVI plus linear lesions in a randomised trial of 589 patients with persistent (follow up
of 18 months) [Verma A et al. N Engl J Med. 2015].
Other approaches for treating persistent AF have
therefore been evaluated, such as PVI plus ablation of
focal sources and rotors, PVI plus isolation of left arterial appendage (LAA), PVI plus ablation of autonomic
ganglia, and PVI plus isolation of the area of fibrosis. The
latter is of interest as it has been independently associated with likelihood of recurrent arrhythmia [Marrouche
NF et al. JAMA. 2014]. Finally, fibrotic areas have been
successfully targeted with box isolation to reduce AF/
atrial tachycardia [Kottkamp H et al. J Cardiovasc
Electrophysiol. 2016]. However, none of these approaches have consistently proven to be successful in adding
benefit over PVI alone, nor have they been shown to
reduce hard endpoints in randomised clinical trials.
A logical approach to prevent AF progression may be
represented by the maintenance of SR as vigourously
and as early as possible. This is under investigation in
two trials: CABANA, which compares ablation with AADs;
and EAST, which evaluates rhythm control with ablation
and AADs against guideline-mandated initial rate control, in patients presenting with their first episode of AF.
CABANA is expected to complete in 2018; EAST in 2019.
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