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© 2017 EDIZIONI MINERVA MEDICA Online version at http://www.minervamedica.it
Minerva Cardioangiologica 2017 ????;65(??):000-000 DOI: 10.23736/S0026-4725.17.04430-9
REVIEW MANAGEMENT OF CARDIAC ARRHYTHMIAS
Targeting ablation strategies and electro-anatomical systems for different atrial fibrillation patterns
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Francesco SANTORO 1, 2 *, Christian H. HEEGER 1, Andreas METZNER 1, Natale D. BRUNETTI 2, Matteo DI BIASE 2, Karl-Heinz KUCK 1, Feifan OUYANG 1
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1Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany; 2Department of Medical and Surgery Science, University of Foggia, Foggia, Italy
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*Corresponding authors: Francesco Santoro, Asklepios Klinik St. Georg, Lohmühlenstr 5, 20099, Hamburg, Germany. E-mail:
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trial fibrillation (AF) is the most common arrhythmia with an increasing prevalence and a high socio-economical health burden. Catheter ablation (CA) is an established and widespread AF treatment. After the initial discovery and abolishment of focal pulmonary vein (PV) activity as AF triggers,1 CA treatment considerably improved over time, pursuing better outcomes, faster, safer and easier procedures. Electrical pulmonary vein isolation (PVI) is the cornerstone of AF treatment.2 In patients with paroxysmal AF, recovered PV conduction
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INTRODUCTIONː Catheter ablation (CA) is an established and widespread treatment option for drug refractory atrial fibrillation (AF). CA has undergone considerable improvements during the last years and several ablation strategies have been proposed for different AF patterns. EVIDENCE ACQUISITIONː The main cornerstone is the electrical isolation of pulmonary veins (PVs) especially among patients with paroxysmal AF. This can be achieved mainly with the use of radiofrequency or cryo-energy. However ablation strategy remains uncertain in patients with persistent AF. EVIDENCE SYNTHESISː Several mapping systems have been developed in order to acquire electrical and anatomical information of the left and right atrium. For patients with persistent atrial fibrillation new systems are able to identify potential AF triggers arising out of the PVs, but the role of ablation of this triggers is still not clear. CONCLUSIONSː Although several improvements have been performed in CA of AF, the main cornerstone of treatment remains the electrical isolation of PVs. This approach provides good clinical results at long-term follow-up in patients with paroxysmal AF. However, the ablation strategy apart from electrical isolation of PV in patients with persistent AF is still not well defined. Further improvement of mapping systems could provide more information about alternative ablation strategies. (Cite this article as: Santoro F, Heeger CH, Metzner A, Brunetti ND, Di Biase M, Kuck KH, et al. Targeting ablation strategies and electro-anatomical systems for different atrial fibrillation patterns. Minerva Cardioangiol 2017;65:______. DOI: 10.23736/S0026-4725.17.04430-9) Key words: Atrial fibrillation - Catheter ablation - Pulmonary veins.
is the most common cause of recurrence, being successfully treated with a second ablation procedure.3 However, In patients with longstanding persistent AF success-rates are lower and AF triggers from a diseased left atrium (LA) are more common, requiring additional substrate modification, defragmentation or linear ablation.4 A distinguished CA approach for such patients is still not standardized. Aim of this review was to evaluate how ablation strategies with electro-anatomic systems can reduce AF recurrence in different pattern of AF.
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TARGETING ABLATION STRATEGIES AND ELECTRO-ANATOMICAL SYSTEMS FOR AF
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Ablation strategy: “Back to the roots! Should we target only the pulmonary veins?”
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Current guidelines define AF as paroxysmal when it is self-terminating, mainly within 48 hours; however paroxysmal AF may continue for up to 7 days. Even an episode of AF treated with electrical cardioversion within the one week can be still classified in this group.5 In case of drug refractory symptomatic paroxysmal AF, catheter ablation (CA) is recommended. Complete PVI is the best documented strategy and can be achieved with different energies. Wide circumferential PVI using radiofrequency (RF) energy is the usual therapeutic approach for the treatment of paroxysmal AF (Figure 1).6 PVI results in stable sinus rhythm in the majority of patients, although repeat procedures are sometimes required. Long-term freedom
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Paroxysmal AF
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Figure 1.—Carto-guided point-by-point electro anatomic map of left atrium, shown with posterior view. Typical example of our current approach for patient with paroxysmal atrial fibrillation. Electrical isolation of left and right pulmonary veins is performed with wide antral circumferential pulmonary vein isolation (red points).
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from arrhythmia was obtained in 46.6% of patients after an initial procedure during a median follow-up period of 4.8 years and in 79.5% after a median of 1 (1 to 3) procedures.7 The most important factor for recurrent arrhythmia is PV reconnection of at least one previously isolated PV, which has been observed in 92% of patients presenting for a repeat procedure. If repeat procedures were performed, targeting the PVs. for re-isolation AF freedom was achieved in 81% of patients.8 In 14% of these patients, this was combined with supplementary ablation of non-PV triggers as identified with provocative maneuvers. Among young patients (age ≤35 years), PVI in paroxysmal AF can provide after a mean of 1.5±0.6 ablation procedures a success rate in term of freedom from AF of 85% at long term follow-up.9 It has not been proven that further extension of the ablation strategy in patients with paroxysmal AF improves clinical results.10, 11 Additional deployment of linear lesion sets (anterior line, posterior line, roof line and posterior box isolation) did not translate into further benefit for sinus rhythm maintenance and resulted mainly in prolonged procedure times.12 Similarly, adjuvant complex fractionated atrial electrogram (CFAE) ablation in addition to standard PVI did not improve outcome in patients with paroxysmal AF.13 By contrast, procedure and fluoroscopy times as well as the risk of adverse atrial tachycardia increased.14 No benefit was shown in repeat procedures for paroxysmal AF if additional linear ablation was performed after re-isolation of the PVs.15 In summary, isolation of the PVs. remains the main target of interventional therapy for paroxysmal AF. Yet, because of the requirement for repeat procedures due to a high rate of recurrence of PV conduction, further improvement of this approach is needed.
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Cryoballoon based ablation The cryoballoon represents an alternative, safe and effective device for PVI.16 PVI is achieved by ostial positioning of a balloon that is cooled by liquid nitrous oxide. The balloon is advanced into the left atrium through a uni-
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directionally steerable sheath combined with a multipolar circular mapping catheter that can be advanced through a central lumen, allowing for real-time recordings of PV electrograms. Furthermore, the mapping catheter enhances maneuvering of the balloon in the left atrium using an ‘over the wire’ technique. Actually is available the new second-generation system (Arctic Front AdvanceTM, Medtronic Inc., Minneapolis, MN, USA) which is mounted with eight injection jets, resulting in more homogenous cooling of the complete distal balloon hemisphere and thereby deploys a more homogenous lesion along the pulmonary vein antrum (Figure 2). The recent published Fire and Ice Trial proved that cryoballoon ablation was non-inferior to RF ablation when comparing efficacy among patients with drug-refractory paroxysmal AF, and there was no significant difference between the two methods with regard to overall safety.17 In this trial 762 patients were enrolled and randomized (378 to cryoballoon ablation and 384 RF ablation). After a mean follow-up of 1.5 years, recurrence rate of AF was similar between the two groups 34.6% vs. 35.9%, respectively (P
