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Archives of cardiovascular diseases
Volume 106, n° 1
pages 36-43 (janvier 2013)
Doi : 10.1016/j.acvd.2012.09.002
Received : 9 April 2012 ;  accepted : 4 September 2012
Predicting favourable outcomes in the setting of radiofrequency catheter ablation of long-standing persistent atrial fibrillation: A pilot study assessing the value of left atrial appendage peak flow velocity
Prévoir les résultats favorables après l’ablation par radiofréquence de la fibrillation auriculaire persistante – Étude pilote sur l’intérêt la mesure de la vélocité de l’auricule gauche auriculaire
 

Stéphane Combes a, , Sophie Jacob b, Nicolas Combes a, Nicole Karam c, Arnaud Chaumeil a, Benoit Guy-Moyat a, Frédéric Treguer a, Antoine Deplagne a, Serge Boveda a, Eloi Marijon a, c, Jean-Paul Albenque a
a Département de Rythmologie, Clinique Pasteur, BP 27617, 43-45, avenue de Lombez, 31076 Toulouse cedex 3, France 
b Laboratoire d’Épidémiologie, IRSN, Fontenay-aux-Roses, France 
c Centre de Recherche Cardiovasculaire de Paris, Inserm U970, Paris, France 

Corresponding author. Fax: +33 5 62 21 16 41.
Summary
Background

Catheter ablation is an effective and potentially curative treatment in patients with atrial fibrillation (AF).

Aim

To test the hypothesis that left atrial appendage peak flow velocity (LAV) assessed by echocardiography can accurately predict successful catheter ablation as well as favourable outcome in the setting of long-standing persistent AF.

Methods

This prospective pilot study enrolled 40 patients with long-standing persistent AF (age 60±11years; persistence of AF 4.2±2years) who underwent a first catheter ablation procedure using a standardized sequential stepwise protocol. LAV was assessed before the catheter ablation procedure along with classical factors (age, sex, left atrial area, AF cycle length, AF duration and left ventricular ejection fraction), all of which were tested using logistic regression for ability to predict restoration of sinus rhythm during catheter ablation as well as absence of recurrence during a 1-year follow-up.

Results

Eighteen patients (45%) experienced AF termination during the procedure and 18 patients (45%) did not develop any recurrence during the first 12months. Multivariable analysis demonstrated that high LAV (>0.3m/s) was the only independent predictor of AF termination (odds ratio 5.91, 95% confidence interval 1.06–32.88; P =0.04) and absence of recurrence at 1year (odds ratio 4.33, 95% confidence interval 1.05–17.81; P =0.04).

Conclusions

This pilot study demonstrated the feasibility and importance of LAV measurement in the setting of long-standing persistent AF to predict successful catheter ablation and favourable mid-term outcome.

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Résumé

L’ablation par cathéter est un traitement efficace et potentiellement curatif chez les patients atteints de fibrillation auriculaire (FA). Nous avons supposé que le pic de vitesse de vidange de l’auricule gauche évalué par échocardiographie transœsophagienne était en mesure de prédire avec précision le succès de l’ablation ainsi que les résultats favorables à moyen terme dans la FA persistante.

Méthodes

Cette étude pilote prospective a recruté 40 patients présentant une FA persistante (âge 60±11ans, persistance de la FA 4,2±2ans) et ayant bénéficié d’une première procédure d’ablation par radiofréquence, utilisant un protocole standardisé étape par étape. Le pic de vitesse de vidange de l’auricule gauche a été évalué avant la procédure d’ablation par cathéter ainsi que les autres facteurs prédictifs classiques (âge, sexe, surface de l’oreillette gauche, la longueur du cycle AF, durée de la FA et la fraction d’éjection ventriculaire gauche). Ces paramètres ont été testés en utilisant une régression logistique pour (i) la restauration du rythme sinusal pendant la procédure d’ablation par cathéter ainsi que (ii) pour l’absence de récidive au cours de la première année de suivi.

Résultats

Dix-huit patients (45%) ont connu un arrêt de la FA pendant la procédure et 18 patients (45%) n’ont pas développé de récidive au cours des 12 premiers mois. L’analyse multivariée a démontré que les vélocités hautes dans l’auricule (>0,3m/s) étaient le seul facteur prédictif indépendant d’arrêt de la FA per procédure (OR=5,91, IC 95% : 1,06 à 32,88, p =0,04) et de l’absence de récidive à un an (OR=4,33, IC à 95% : de 1,05 à 17,81, p =0,04).

Conclusions

Cette étude pilote a démontré la faisabilité et l’importance de la mesure de la vélocité dans l’auricule gauche avant l’ablation de FA persistante pour prédire le succès de l’ablation par cathéter et les résultats favorables à moyen terme.

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Keywords : Atrial fibrillation, Left atrial appendage peak flow velocity, Catheter ablation, Echocardiography, Radiofrequency

Mots clés : Fibrillation auriculaire, Vélocité de l’auricule gauche, Ablation par radiofréquence, Échocardiographie

Abbreviations : AF, CI, ECG, IQR, LAV, OR, ROC


Background

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. If untreated, it leads to an increase in cardiovascular morbidity–particularly embolic stroke–and mortality [1]. Catheter ablation has been demonstrated to be a very effective and potentially curative treatment in patients with paroxysmal AF [2, 3, 4]. In contrast, results regarding persistent AF, especially long-standing persistent AF, are more controversial, with largely varying success rates [5, 6, 7]. Accordingly, in the setting of long-standing persistent AF, the optimization of candidate selection should improve the success rate of these procedures and therefore favourably increase the benefit/risk ratio of this invasive strategy.

A number of variables have been found to have a potential role in predicting successful catheter ablation and recurrence risk: duration of AF; surface electrocardiogram AF cycle length; patient age; left atrial diameter; left ventricular function; and, more recently, magnetic resonance imaging delayed enhancement of the left atrium [8, 9, 10]. Taken separately, however, the predictive value of each of these variables remains relatively low and of limited interest in routine clinical practice.

Given the pathophysiology of AF, we hypothesized that high left atrial appendage peak flow velocity (LAV) assessed by transesophageal echocardiography before catheter ablation procedure would accurately predict successful procedure and favourable outcome.

Methods
Study population and exclusion criteria

Forty patients who had undergone first-time radiofrequency catheter ablation for long-standing persistent AF were enrolled from January 2009 and followed until May 2010 (ClinicalTrials.gov ID: NCT01144858). Long-standing persistent AF was defined as AF that has been present for 1year or more, resistant to at least one electrical or pharmacological cardioversion and for which a rhythm control strategy was decided. Exclusion criteria included: age<18 or >80years; severe valvular disease requiring surgery; valve prosthesis; known severe coronary artery disease; atrial and/or ventricular thrombosis; New York Heart Association functional class III–IV; cerebrovascular disease; pulmonary embolism; and latent or manifest hyperthyroidism. All patients gave their written informed consent.

Echocardiography study

A complete echocardiographic evaluation was carried out within 48hours before the procedure using the conventional transthoracic approach and then transoesophageal echocardiography was carried out by two different physicians in a blinded fashion.

First, conventional transthoracic echocardiography was performed before and after AF catheter ablation (IE33 System; Philips Medical Systems, Andover, MA, USA) with routine echocardiographic measurements, using parasternal short and long axes, and apical four- and two-chamber views. The left atrium area was obtained via apical four-chamber zoomed views of the left atrium. Images and pulse Doppler flows of mitral inflow and tissue Doppler imaging at the mitral annulus were acquired from the four-chamber views.

Second, all patients were evaluated before catheter ablation by complete transoesophageal echocardiography with multiplane probes using a 7-MHz transducer (Vivid i; General Electric Medical Health, Horten, Norway). Left atrial spontaneous contrast and thrombus were sought. After a complete analysis of the left atrial appendage at the base of the heart with rotation of the probe between 0° and 180°, the incidence with the best alignment of the cursor with the appendage long axis was selected. The cursor was placed at the entry of the appendage for pulsed Doppler analysis and we considered the average value of 10 consecutive fibrillatory emptying waves (Figure 1) [11].



Figure 1


Figure 1. 

A. Pulsed Doppler tracing of left atrial appendage obtained by transoesophageal echocardiography showing left atrial appendage peak flow velocity (LAV) at the mouth of the appendage at 80° in a patient who achieved successful atrial fibrillation (AF) termination (0.42m/s). B. Low LAV at the mouth of the appendage at 43° in a patient in whom persistent AF was not terminated during the procedure (0.22m/s).

Zoom

Outcome measures

The primary outcome was restoration of sinus rhythm during the catheter ablation procedure. The second outcome was absence of recurrence of atrial arrhythmias (AF, atrial tachycardia or flutter) during the year following the procedure.

Electrophysiological study and catheter ablation procedure

All patients received effective anticoagulation therapy (vitamin K antagonists, target international normalized ratio [IQR] of 2–3) for more than 1month before ablation. This therapy was interrupted at least 48hours before the procedure, with a heparin bridge. All antiarrhythmic drugs were discontinued 1week before the procedure, except for amiodarone, which was maintained.

The electrophysiological study was performed under general anaesthesia using a standard protocol. The following catheters were introduced via the femoral vein: a steerable quadripolar catheter (Xtrem®; Sorin Group, Le Plessis-Robinson, France) was positioned within the coronary sinus; a circumferential mapping catheter (Lasso; Biosense Webster, Diamond Bar, CA, USA) was introduced after transseptal access; and a 4-mm externally irrigated-tip ablation catheter (Thermocool, Biosense Webster) was used for mapping and ablation. After transseptal access, a single bolus of heparin (100IU/kg body weight) was administered. The infusion was adjusted to maintain an activated coagulation time of 300s or more. The transseptal sheath was also continuously infused with heparinized saline during the procedure.

Surface electrocardiograms (ECGs) and endocardial electrograms were continuously monitored and recorded for off-line analysis (Bard Electrophysiology, Lowell, MA, USA). Following transseptal catheterization, left atrial and coronary sinus electroanatomical mapping (Carto 3; Biosense Webster) was performed during spontaneous AF. Computed tomography registration and fusion of left atrial reconstructions with the electroanatomical map were subsequently performed. Endocardial AF cycle length was determined from intracardiac recordings at the left atrial appendage before ablation and was averaged for 30 consecutive intervals.

In all patients, sequential stepwise ablation described by O’Neill et al. [6], was performed by the same operator, blinded to the echocardiographic data. The procedure was terminated with the step that allowed AF conversion into sinus rhythm and no antiarrhythmic treatment was prescribed during the procedural period or during the procedure. In all cases, circular and linear lesions were verified after sinus rhythm restoration. The first step involved pulmonary vein isolation. The second step included linear ablation in the left atrium: a roof line was drawn between the right and left superior pulmonary veins and, if AF persisted, a mitral isthmus line was drawn from the mitral annulus to the left inferior pulmonary vein and coronary sinus defragmentation was performed. The third step consisted of electrogram-based ablation of complex fractionated atrial electrograms in the left and right atria [5]. Complex fractionated atrial electrogram sites were tagged on the geometry obtained from three-dimensional mapping during AF. Lastly, a cavotricuspid isthmus line was performed only in patients with a history of common atrial flutter with ECG documentation.

When AF was converted to a regular arrhythmia, activation and entrainment mapping were performed to differentiate between focal and re-entrant mechanisms. Atrial tachycardias were targeted for ablation until sinus rhythm was achieved. When sinus rhythm was not restored by ablation, AF or atrial tachycardia was terminated by electrical cardioversion and the procedure was considered as a failure. After restoration of sinus rhythm, assessment of conduction block across the lines was performed in all patients [12]. When necessary, supplemental radiofrequency energy was delivered to achieve block.

Discharge, follow-up plan and AF recurrence assessment

Treatment with vitamin K antagonists was resumed 1day after the procedure and patients were discharged on day 3 receiving low-molecular-weight heparin until they had two consecutive international normalized ratios>2. Patients were assessed before discharge and at the third, sixth and 12th months by clinical interview, echocardiography and 24-h Holter monitoring. In addition, patients were instructed to call their cardiologist in case of sustained palpitation, for immediate ECG recording. Vitamin K antagonists were prescribed for a minimum of 3months and potentially discontinued in case of low thromboembolic score (CHADS2 score 0 or 1). Amiodarone was continued for at least 3months in patients who were receiving amiodarone before the procedure and was interrupted in case of no recurrence at 3months. Recurrence was defined as any symptomatic or asymptomatic atrial arrhythmia lasting>30s; it was evidenced by Holter monitoring at 3, 6 and 12months or by 12-lead ECG in case of symptomatic palpitation at clinical interview.

Statistical analysis

Categorical variables are expressed as number and proportion, and continuous variables are expressed as mean±standard deviation. Comparison of baseline characteristics of patients with and without AF termination by catheter ablation was performed using the χ2 test or Fisher’s exact test (as appropriate) for categorical variables and Wilcoxon’s test for continuous variables. All tests were two-sided. A P value<0.05 was considered statistically significant.

LAV (highly associated with favourable outcome) was studied by analysis of receiver operating characteristics (ROC) to determine optimal cutoff values for the prediction of successful catheter ablation. ROC was evaluated using a plot of the true positive fraction (sensitivity) versus the true negative fraction (1–specificity) with a continuously varying decision threshold. The best cutoff value was defined as the point combining the highest sensitivity and specificity.

Age, duration of AF, LAV, left ventricular ejection fraction, left atrial area and AF cycle length from the left atrial appendage were considered in a logistic regression model to identify criteria associated with successful catheter ablation procedure. Categorized variables with a P value<0.20 in univariate analysis were then considered in a logistic regression model to identify independent predictors of AF termination by ablation. A similar analysis was performed regarding the absence of AF recurrence during the 1-year period. All statistical analyses were performed using SAS software, version 9.1 (SAS Institute, Cary, NC, USA).

Results
Patient characteristics

The mean age of patients was 59.9±11years and 34 were men (85%). The mean duration of AF was 4.2±2years; all (except one patient with a formal contraindication) were receiving amiodarone at the time of the procedure. All patients were symptomatic for dyspnoea and/or palpitations. The mean left ventricular ejection fraction was normal (59.4±9%) despite the presence of structural heart disease in 23 patients (57%), mainly related to ischaemic heart disease. Echocardiography demonstrated moderate-to-severe left atrial enlargement with a mean left atrial area of 26±7.3cm2 (IQR, 20 to 30). Transmitral flow variables in persistent AF (peak E and E/e’) were measured (82.3±29.8cm/s and 13.1±2.1, respectively). Spontaneous echo contrast was found in the left atrium in 42% of patients. The group of patients with an LAV<0.30m/s had significantly more spontaneous echo contrast than the group of patients with a higher LAV (63% vs 11%; P =0.001). An electrophysiology study found a mean AF cycle length in the left atrial appendage of around 176±20ms. LAV was 0.30±0.12m/s (IQR, 0.24 to 0.34) (Figure 1).

Procedural results

The results are summarized in Figure 2. Twenty-six of the 40 patients (65%) had acute termination of AF during radiofrequency ablation (direct AF termination to sinus rhythm or via atrial tachycardia) and 18 patients (45%) in whom sinus rhythm was restored without electrical cardioversion.



Figure 2


Figure 2. 

Flow chart of the study. AF: atrial fibrillation; AT: atrial tachycardia; DCC: direct current cardioversion; LAV: left appendage peak flow velocity; SR: sinus rhythm.

Zoom

Among the 10 patients with direct termination to sinus rhythm, AF termination occurred in two patients (20%) during pulmonary vein isolation and in four patients (40%) during line ablation. Defragmentation of the left atria resulted in direct termination to sinus rhythm in three patients (30%). Defragmentation of the right atria led to termination directly to sinus rhythm in one patient (10%).

AF organized into atrial tachycardia in 16 patients, eight of whom converted into sinus rhythm with further ablation. The atrial tachycardia mechanisms were perimitral (n =4), cavotricuspid isthmus dependent (n =1) and focal (n =3). Among the 16 patients with atrial tachycardia, two had AF organization to atrial tachycardia after pulmonary vein isolation, two after roof line, three after mitral isthmus line and six after coronary sinus defragmentation. In the additional three patients, AF organized into atrial tachycardia during subsequent complex fractionated atrial electrogram ablation.

The 14 patients (35%) who did not experience AF termination after stepwise ablation underwent electrical cardioversion.

Mean procedural time was 201±43minutes with a fluoroscopy time of 46±19minutes.

Prediction of AF termination during catheter ablation procedure

Comparison of baseline characteristics between patients with and without AF termination is shown in Table 1. Using regression analysis, shorter AF duration (odds ratio [OR] 4.86, 95% confidence interval [CI] 1.21–19.47; P =0.03), high LVA (OR 8.67, 95% CI 2.01–37.36; P <0.01), smaller left atrial area (OR 3.81, 95% CI 0.99–14.64; P =0.05) and longer AF cycle length in the left atrial appendage (OR 4.89, 95% CI 1.25–19.19; P =0.02) were all significantly associated with perprocedural AF termination (Table 2). However, in multivariable analysis, only LAV remained significant (OR 5.91, 95% CI 1.06–32.88; P =0.04).

Based on ROC curve analysis of LAV (Figure 3), the optimal cutoff point was 0.30m/s, with a specificity of 72.8% and a sensitivity of 77.8% for predicting procedural AF termination; the area under the curve was estimated to be 0.81 (95% CI 0.680.95; P <0.001). The cutoff point of 0.30m/s corresponded to positive and negative predictive values of 70% and 80%, respectively. Moreover, by combining both LAV0.30m/s and left atrial area<25cm2, the specificity reached 100% for predicting procedural AF termination (sensitivity, 50%; positive predictive value, 100%; negative predictive value, 71%).



Figure 3


Figure 3. 

Receiver operating characteristics curve showing the prognostic value of left atrial appendage peak flow velocity for the prediction of atrial fibrillation (AF) termination after catheter ablation. The optimal cutoff point was 0.30m/s, with a specificity of 72.8% and a sensitivity of 77.8% for predicting procedural AF termination.

Zoom

Prediction of no atrial arrhythmia recurrences during the 1-year follow-up

The 1-year follow-up was completed in all patients. Overall, sinus rhythm was maintained in 18 patients (45%). Eight patients from the no termination AF group were in persistent sinus rhythm during the follow-up at 1year. AF cycle length was longer in patients without AF recurrence (167.2±16ms vs 183.9±17ms; P =0.01). There were no significant differences regarding left atrial area, AF duration, left ventricular ejection fraction and demographics between the two groups. In contrast, LAV was higher in the recurrence-free group during the follow-up (0.25±0.10m/s vs 0.36±0.13m/s; P =0.006); AF recurrence rates at 1year according to LAV (cutoff value fixed at 0.30m/s) differed significantly (75% vs 35%; P =0.01) (Figure 2). Logistic regression analysis is presented in Table 3. In multivariable analysis, only LAV remained significant for predicting AF recurrence (OR 4.33, 95% CI 1.05–17.81; P =0.04).

Discussion

In this pilot study, carried out in the setting of long-standing AF, LAV measurement has been found to be of particular interest in predicting procedural success of catheter ablation as well as arrhythmia recurrence rate at mid term.

Catheter ablation of AF has been used for about 10years. For long-standing persistent AF, ablation strategies vary considerably between centres and success rates range between 38% and >62% after one procedure [13, 14, 15]. To improve global results, optimization of patient selection must be carried out; identification of predictors of favourable outcomes, using minimally invasive measurements, is crucial in this setting.

The concept of a link between LAV and clinical outcome is based on a solid rationale. Important literature emphasized the central role of atrial tissue mass and histology in the pathogenesis of AF [16]. In persistent AF, the left atrium undergoes remodelling processes that are believed to be pathophysiological factors for persistence of AF [17]. In addition to structural remodelling mainly focused on the intercellular matrix, AF causes atrial electrophysiological remodelling, changes in connexin density and distribution, cellular structural remodelling, myolysis and glycogen accumulation, according to the well-known concept summarized as ‘AF begets AF’ [18, 19, 20]. LA function is difficult to assess non-invasively and some studies have evaluated left atrial appendage function–particularly LAV–as a surrogate [21]. Peak left atrial appendage emptying velocity appears to be a complex variable that depends on left atrial function [22]. Left atrium and left atrial appendage are two distinct histological structures. Because of its increased distensibility, the left atrial appendage may increase its haemodynamic function by modulating left atrial pressure-volume relations in states of increased left atrial pressure and volume overload or atrial fibrosis [23]. This replacement of atrial contractile tissue by fibrosis supports our hypothesis that a lower LAV would be associated with a lower rate of catheter ablation procedure success and a higher rate of recurrence at mid term.

Only a few previous studies have investigated the importance of LAV measured by transoesophageal echocardiography before AF cardioversion. These studies showed that LAV is one of the strongest predictors of atrial dysfunction and sinus rhythm persistence after AF electrical cardioversion [24, 25]. In a prospective multicentre study of 193 patients, Antonielli et al. [26] showed that LAV>0.40m/s could independently predict sinus rhythm persistence at 1year after successful electrical cardioversion, with a negative predictive value of 66% and a positive predictive value of 73%. To our knowledge, our pilot study is the first demonstrating that high LAV is a predictor of immediate and mid-term success after AF catheter ablation.

A number of series of patients treated for long-standing persistent AF demonstrated that perprocedural termination of persistent AF is associated with a better clinical outcome [13, 27, 28]. As in our study, AF termination and long-term persistence of sinus rhythm after AF ablation were strongly linked, with very similar predicting factors [29]. In a study of catheter ablation for persistent AF, Matsuo et al. demonstrated that long AF cycle length on surface electrocardiograms is independently associated with sinus rhythm persistence [9]. Left atrial dimension, a well-known marker of left atrial disease, has been found to be inferior to AF cycle length as a predictor of the occurrence of subsequent atrial tachycardia [30, 31]. In a group of 148 patients, Berruezo et al. demonstrated that the anterior-posterior left atrial diameter was an independent predictor of AF recurrence after AF catheter ablation [32]. These findings were confirmed by Shin et al. who found left atrial volume to be a significant predictor of AF recurrence after catheter ablation in a group of 68 patients [33]. In our study, left atrial dimension was significantly associated with perprocedural AF termination in univariate analysis. After adjustment, we noted only a slight trend for predicting arrhythmia recurrence, which remained non-significant mainly due to the limited number of patients enrolled in this pilot study. Significantly dilated atria are generally thought to be associated with a high degree of atrial remodelling, which limits the efficacy of catheter ablation. Recent studies [34] demonstrated that the degree of fibrosis detected by sophisticated imaging systems was highly associated with procedural success and outcome, emphasizing our hypothesis that a low LAV is a predictor of an unfavourable outcome; a recent study by Mahnkopf et al. demonstrated that increased delayed enhancement within the left atrial wall on magnetic resonance imaging is strongly associated with AF recurrence, regardless of the type of AF and the patient’s comorbidities [35]. Additionally, in a cohort of 81 patients, Oakes et al. reported that late gadolinium enhancement of the left atrium on magnetic resonance imaging was correlated with the extent of left atrial fibrosis measured by a voltage map and with the odds of procedural success [10].

Study limitations

Although our study is the first to prospectively evaluate the value of LA appendage velocity in the setting of long-standing persistent AF, we acknowledge some limitations. First, our sample size was small. However, in spite of this relatively low number of patients, the predictive value of LAV was highly significant. Second, as is usual in AF studies, ECG and periodic Holter monitoring may have led to some degree of underestimation of recurrence rates.

Conclusions

In conclusion, in the setting of long-standing persistent AF, high LAV appears to be particularly efficient in accurately predicting AF termination by radiofrequency catheter ablation as well as persistence of sinus rhythm during follow-up. Our results should encourage further studies to confirm the value of considering LAV in routine practice.

Disclosure of interest

The authors declare that they have no conflicts of interest concerning this article.

References

Wolf P.A., Abbott R.D., Kannel W.B. Atrial fibrillation: a major contributor to stroke in the elderly. The Framingham Study Arch Intern Med 1987 ;  147 : 1561-1564 [cross-ref]
Leong-Sit P., Zado E., Callans D.J., and al. Efficacy and risk of atrial fibrillation ablation before 45years of age Circ Arrhythm Electrophysiol 2010 ;  3 : 452-457 [cross-ref]
Tzou W.S., Marchlinski F.E., Zado E.S., and al. Long-term outcome after successful catheter ablation of atrial fibrillation Circ Arrhythm Electrophysiol 2010 ;  3 : 237-242 [cross-ref]
Wilber D.J., Pappone C., Neuzil P., and al. Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial JAMA 2010 ;  303 : 333-340 [cross-ref]
Nademanee K., McKenzie J., Kosar E., and al. A new approach for catheter ablation of atrial fibrillation: mapping of the electrophysiologic substrate J Am Coll Cardiol 2004 ;  43 : 2044-2053 [cross-ref]
O’Neill M.D., Jais P., Takahashi Y., and al. The stepwise ablation approach for chronic atrial fibrillation--evidence for a cumulative effect J Interv Card Electrophysiol 2006 ;  16 : 153-167
Oral H., Pappone C., Chugh A., and al. Circumferential pulmonary-vein ablation for chronic atrial fibrillation N Engl J Med 2006 ;  354 : 934-941 [cross-ref]
Lo L.W., Lin Y.J., Tsao H.M., and al. The impact of left atrial size on long-term outcome of catheter ablation of chronic atrial fibrillation J Cardiovasc Electrophysiol 2009 ;  20 : 1211-1216 [cross-ref]
Matsuo S., Lellouche N., Wright M., and al. Clinical predictors of termination and clinical outcome of catheter ablation for persistent atrial fibrillation J Am Coll Cardiol 2009 ;  54 : 788-795 [cross-ref]
Oakes R.S., Badger T.J., Kholmovski E.G., and al. Detection and quantification of left atrial structural remodeling with delayed-enhancement magnetic resonance imaging in patients with atrial fibrillation Circulation 2009 ;  119 : 1758-1767 [cross-ref]
To A.C., Flamm S.D., Marwick T.H., and al. Clinical utility of multimodality LA imaging: assessment of size, function, and structure JACC Cardiovasc Imaging 2011 ;  4 : 788-798 [cross-ref]
Jais P., Hocini M., O’Neill M.D., and al. How to perform linear lesions Heart Rhythm 2007 ;  4 : 803-809 [cross-ref]
Brooks A.G., Stiles M.K., Laborderie J., and al. Outcomes of long-standing persistent atrial fibrillation ablation: a systematic review Heart Rhythm 2010 ;  7 : 835-846 [cross-ref]
Haissaguerre M., Hocini M., Sanders P., and al. Catheter ablation of long-lasting persistent atrial fibrillation: clinical outcome and mechanisms of subsequent arrhythmias J Cardiovasc Electrophysiol 2005 ;  16 : 1138-1147 [cross-ref]
Willems S., Klemm H., Rostock T., and al. Substrate modification combined with pulmonary vein isolation improves outcome of catheter ablation in patients with persistent atrial fibrillation: a prospective randomized comparison Eur Heart J 2006 ;  27 : 2871-2878 [cross-ref]
Garrey W.E. The nature of fibrillary contraction of the heart - its relation to tissue mass and form Am J Physiol 1914 ;  33 : 397-414
Ausma J., Wijffels M., van Eys G., and al. Dedifferentiation of atrial cardiomyocytes as a result of chronic atrial fibrillation Am J Pathol 1997 ;  151 : 985-997
Aime-Sempe C., Folliguet T., Rucker-Martin C., and al. Myocardial cell death in fibrillating and dilated human right atria J Am Coll Cardiol 1999 ;  34 : 1577-1586 [cross-ref]
Ausma J., Wijffels M., Thone F., and al. Structural changes of atrial myocardium due to sustained atrial fibrillation in the goat Circulation 1997 ;  96 : 3157-3163 [cross-ref]
Wijffels M.C., Kirchhof C.J., Dorland R., and al. Atrial fibrillation begets atrial fibrillation. A study in awake chronically instrumented goats Circulation 1995 ;  92 : 1954-1968 [cross-ref]
Agmon Y., Khandheria B.K., Meissner I., and al. Are left atrial appendage flow velocities adequate surrogates of global left atrial function? A population-based transthoracic and transesophageal echocardiographic study J Am Soc Echocardiogr 2002 ;  15 : 433-440 [inter-ref]
Donal E., Grimm R.A., Yamada H., and al. Usefulness of Doppler assessment of pulmonary vein and left atrial appendage flow following pulmonary vein isolation of chronic atrial fibrillation in predicting recovery of left atrial function Am J Cardiol 2005 ;  95 : 941-947 [inter-ref]
Davis C.A., Rembert J.C., Greenfield J.C. Compliance of left atrium with and without left atrium appendage Am J Physiol 1990 ;  259 : H1006-H1008
Grimm R.A., Stewart W.J., Maloney J.D., and al. Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo contrast: characterization by simultaneous transesophageal echocardiography J Am Coll Cardiol 1993 ;  22 : 1359-1366 [cross-ref]
Ito T., Suwa M., Otake Y., and al. Assessment of left atrial appendage function after cardioversion of atrial fibrillation: relation to left atrial mechanical function Am Heart J 1998 ;  135 : 1020-1026 [inter-ref]
Antonielli E., Pizzuti A., Palinkas A., and al. Clinical value of left atrial appendage flow for prediction of long-term sinus rhythm maintenance in patients with nonvalvular atrial fibrillation J Am Coll Cardiol 2002 ;  39 : 1443-1449 [cross-ref]
O’Neill M.D., Wright M., Knecht S., and al. Long-term follow-up of persistent atrial fibrillation ablation using termination as a procedural endpoint Eur Heart J 2009 ;  30 : 1105-1112
Rostock T., Steven D., Hoffmann B., and al. Chronic atrial fibrillation is a biatrial arrhythmia: data from catheter ablation of chronic atrial fibrillation aiming arrhythmia termination using a sequential ablation approach Circ Arrhythm Electrophysiol 2008 ;  1 : 344-353 [cross-ref]
McCready J.W., Smedley T., Lambiase P.D., and al. Predictors of recurrence following radiofrequency ablation for persistent atrial fibrillation Europace 2011 ;  13 : 355-361 [cross-ref]
Arya A., Hindricks G., Sommer P., and al. Long-term results and the predictors of outcome of catheter ablation of atrial fibrillation using steerable sheath catheter navigation after single procedure in 674 patients Europace 2010 ;  12 : 173-180 [cross-ref]
Drewitz I., Willems S., Salukhe T.V., and al. Atrial fibrillation cycle length is a sole independent predictor of a substrate for consecutive arrhythmias in patients with persistent atrial fibrillation Circ Arrhythm Electrophysiol 2010 ;  3 : 351-360 [cross-ref]
Berruezo A., Tamborero D., Mont L., and al. Pre-procedural predictors of atrial fibrillation recurrence after circumferential pulmonary vein ablation Eur Heart J 2007 ;  28 : 836-841 [cross-ref]
Shin S.H., Park M.Y., Oh W.J., and al. Left atrial volume is a predictor of atrial fibrillation recurrence after catheter ablation J Am Soc Echocardiogr 2008 ;  21 : 697-702 [cross-ref]
Akoum N., Daccarett M., McGann C., and al. Atrial fibrosis helps select the appropriate patient and strategy in catheter ablation of atrial fibrillation: a DE-MRI guided approach J Cardiovasc Electrophysiol 2011 ;  22 : 16-22
Mahnkopf C., Badger T.J., Burgon N.S., and al. Evaluation of the left atrial substrate in patients with lone atrial fibrillation using delayed-enhanced MRI: implications for disease progression and response to catheter ablation Heart Rhythm 2010 ;  7 : 1475-1481 [cross-ref]



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