S-23
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Clinical impact of
electroanatomically guided catheter compartmentation of human atria in the treatment of
paroxysmal atrial fibrillation
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Carlo Pappone, Giuseppe Oreto*,
Francesco Furlanello, Maria Luisa Loricchio, Gabriele Vicedomini, Stefano Bianchi, Shlomo
Shpun**, Cristoforo D'Ascia, Maria Pia Calabro*, Cosimo Dicandia, Shlomo A. Ben-Haim**,
Tiziana Russo, Sergio Chierchia.
Cardiology Department, Hospital S. Raffaele, Milan, *Cardiology Department, University of
Messina, Messina, Italy, **Cardiovascular System Laboratory, Rappaport Faculty of
Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Abstract
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Current therapeutic strategies for atrial fibrillation
(AF) include antiarrhythmic drugs, aimed either at restoring and maintaining sinus rhythm
or at reducing ventricular rate, and electrical cardioversion. Alternative treatments,
such as catheter ablation or modulation of the atrioventricular (AV) node, implantation of
an atrial defibrillator, or surgical procedures, have been also proposed. Very recently,
the possibility of treating AF by means of catheter ablation has been reported1-4.
Ablation treatment for the suppression of AF is based on the hypothesis that without a
sufficient atrial mass in which to operate, multiple reentrant wavelets sufficient in
number to perpetuate AF cannot coexist. If so, AF may be cured by dividing the atria into
several areas electrically isolated from each other. This procedure was originally applied
by cardiac surgeons5-7. Following the early surgical
methods of LA isolation8 and "corridor"
operation9,10, which, while not specifically aimed at
avoiding all the problems related to AF, were able to solve some of them, Cox et al6 introduced the maze procedure. This is a surgical
technique carried out by placing numerous incisions in both atria, producing multiple
electrically isolated atrial segments that can still be depolarized by a sinus impulse.
Success of the procedure is high even in patients with advanced atrial disease: sinus
rhythm and mechanical atrial function are restored, with low thromboembolic risk in the
absence of anticoagulation.
The original results of Cox et al have been confirmed by other investigators7-11. More recently, a different surgical procedure
designed for cure of AF has been presented by Shyu et al12
and defined as "compartment operation". This procedure utilized one single LA
incision designed to divide the atrial mass into two compartments, one made of the LA free
wall and the other comprising the atrial septum and the RA; in approximately one half of
patients a second lesion was created in the RA. In the compartment operation the incision
pattern was far less extensive than in the maze procedure, but the results, although
obtained in a relatively limited series, were attractive (immediate sinus rhythm
restoration in 91% of patients and maintenance of sinus rhythm for > 6 months in 64% of
patients with mitral valve disease and chronic AF). These observations published by Shyu
et al12 raise questions regarding the extent of the
atrial lesion(s) to prevent initiation and/or maintenance of AF, and the possible
existence of critical areas in which limited lesions could be sufficient to cure AF. The
above questions are unanswered at present.
The favorable results achieved by surgeons led to preliminary investigation of RF
catheter ablation of AF in patients with either paroxysmal or persistent AF1-4. Each of these studies utilized fluoroscopic guidance
of single standard ablation electrodes or experimental multielectrode catheters. Ablation
was performed in the RA and/or LA. Due to limitations of the fluoroscopic technique, none
of the studies could adequately assess the degree of success with which the lesions had
been created, and thus no insight into the relationship between lesion success and
procedural success could be gained. Despite this, reasonable rates of AF suppression were
observed, and morbidity rates were acceptably low. There have also been several promising
basic research reports that investigated the response of the atria to RF catheter ablation
for the creation of linear lesions13-23. The approach
to lesion generation in these preparations has generally been epicardial, under direct
vision; complications include creation of more uniform atrial arrhythmias (atrial
tachycardia or flutter), as well as transient atrial mechanical dysfunction20.
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Key Words
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Atrial fibrillation – electrophisiology
non-fluoroscopic electro-anatomical mapping, ablation of arrythmogenic substrates, OA
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