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Archives of cardiovascular diseases
Volume 110, n° 8-9
pages 447-455 (août 2017)
Doi : 10.1016/j.acvd.2016.11.005
Received : 21 July 2016 ;  accepted : 30 November 2016
The usefulness of global left atrial strain for predicting atrial fibrillation recurrence after catheter ablation in patients with persistent and paroxysmal atrial fibrillation
Utilité du strain global atrial gauche pour prédire la récidive de fibrillation atriale après ablation chez des patients ayant une fibrillation atriale persistante ou paroxystique
 

Xin-Xin Ma, Yue-Li Zhang , Bing Hu, Meng-Ruo Zhu, Wen-Jun Jiang, Man Wang, Dong-Yan Zheng, Xiao-Pei Xue
 Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, No. 600 Yishan Road, 200233 Shanghai, China 

Corresponding author.
Summary
Background

Given the potential complications of atrial fibrillation (AF) recurrence after ablation, better predictors of the effectiveness of the procedure are necessary to guide patient selection.

Aim

This prospective study was conducted to evaluate the clinical relevance of global left atrial longitudinal strain (GLAS) and AF recurrence after catheter ablation.

Methods

In 115 consecutive patients with AF (persistent, n =62; paroxysmal, n =53), transthoracic echocardiography was performed before catheter ablation to assess baseline left atrial mechanical function using speckle tracking echocardiography (STE).

Results

After 12 months of follow-up, 22 (35.5%) patients in the persistent AF group and 15 (28.3%) in the paroxysmal AF group exhibited AF recurrence. In both the paroxysmal and persistent AF populations, patients with recurrence presented with significantly impaired GLAS compared with patients without recurrence. Patients with recurrence also had a significantly higher pro-B-type natriuretic peptide concentration. A receiver operator curve analysis yielded area under the curve values of 0.94 and 0.86 for paroxysmal and persistent AF, respectively. In a multivariable Cox proportional-hazards analysis, GLAS was an independent predictor of AF recurrence after catheter ablation in both the paroxysmal AF group (hazard ratio: 0.79, 95% confidence interval: 0.67–0.96; P= 0.01) and the persistent AF group (hazard ratio: 0.81, 95% confidence interval: 0.71–0.93; P =0.004).

Conclusions

In both paroxysmal and persistent AF, decreased baseline left atrial deformation capabilities assessed by two-dimensional STE can help to identify patients at high risk of AF recurrence after catheter ablation. This variable may help to guide candidate selection and improve therapeutic strategies.

The full text of this article is available in PDF format.
Résumé
Justification

Du fait du risque de complications potentielles à type de récurrences au décours d’une ablation de fibrillation atriale, les prédicteurs d’efficacité de la procédure sont nécessaires pour guider la sélection des patients. Cette étude prospective a été conduite pour évaluer la pertinence clinique de l’évaluation du strain longitudinal global auriculaire gauche (GLAS) et la récurrence de fibrillation atriale (FA) après ablation (CA).

Méthode

Cent quinze patients consécutifs en fibrillation atriale (62 persistantes, 53 paroxystiques) ont été évalués par échographie transthoracique (TTE) avant la procédure d’ablation afin de déterminer la fonction mécanique atriale gauche utilisant la technique du Speckle (déformation myocardique).

Résultats

Au cours d’un suivi de 12 mois, 22 patients (35,5 %) ont présenté une récidive de fibrillation atriale dans le groupe FA persistante et 15 patients (28,3 %) dans le groupe FA paroxystique. Dans les deux groupes, les patients ayant une récidive de FA avaient une altération du strain longitudinal global auriculaire gauche comparativement aux patients sans récurrence de FA. De plus, les patients ayant une récurrence de FA avaient un taux de pro-BNP significativement plus élevé. L’analyse des courbes ROC rapportait une valeur de 0,94 pour la FA paroxystique et 0,86 pour la FA persistante. L’analyse multivariée (Cox) a montré que le strain longitudinal global auriculaire gauche était un prédicteur indépendant de la récidive de la FA dans les deux groupes, FA paroxystique (hazard ratio : 0,79, IC 95 % : 0,67–0,96, p =0,01) et dans le groupe FA persistante (hazard ratio : 0,81, IC 95 % : 0,71–0,93, p =0,004).

Conclusion

Tant dans la FA paroxystique que persistante, l’altération de la déformation auriculaire gauche étudiée par technique du Speckle pourrait contribuer à identifier les patients à haut risque de récurrence de FA au décours d’une procédure d’ablation. Ce paramètre pourrait contribuer à sélectionner les patients candidats à cette procédure et donc à améliorer les stratégies thérapeutiques.

The full text of this article is available in PDF format.

Keywords : Atrial fibrillation, Catheter ablation, LA strain, Atrial function

Mots clés : Fibrillation atriale, Ablation par cathéter, Strain auriculaire gauche, Fonction auriculaire gauche

Abbreviations : 2D, 2DSTE, AF, AUC, CI, GLAS, LA, LAVImax, LV, LVEF, MSR, pro-BNP, ROC


Background

In recent years, catheter ablation has become the dominant treatment for patients with drug-refractory atrial fibrillation (AF). However, catheter ablation is also associated with potential severe complications and a considerable recurrence rate for AF [1, 2]. A clear need exists for better delineation of the AF substrate, and the identification of candidates who are most likely to benefit from catheter ablation.

Multiple studies have demonstrated that dilatation of the left atrium (LA), a long duration of AF and advanced age are correlated with worse AF ablation outcomes [3, 4, 5]. Recently, two-dimensional speckle tracking echocardiography (2DSTE) has been widely accepted as an innovative technology to evaluate the mechanics, function, remodelling and reverse remodelling of the LA in patients with AF; 2DSTE results are also strongly associated with cardiac magnetic resonance imaging results [6, 7, 8]. Thus, we investigated global left atrial longitudinal strain (GLAS), to analyse atrial function abnormalities and predict recurrence of AF in patients with paroxysmal and persistent AF undergoing catheter ablation.

Methods
Study population

One hundred and 15 consecutive patients who underwent first-time catheter ablation for paroxysmal or persistent AF between March 2013 and March 2015 were followed prospectively. All patients who had baseline transthoracic echocardiography performed while in sinus rhythm or AF rhythm before ablation, and who had a preserved (>55%) left ventricular ejection fraction (LVEF) were included. Patients were excluded for the following reasons: age<18 years; valvular heart disease or a history of cardiac surgery; malignant disease; hypothyroidism; absence of clinical follow-up; myocardial infarction; and poor echocardiography images. This study was approved by the institutional review board of the Sixth People's Hospital, and all patients gave their written informed consent.

Echocardiography

All patients underwent comprehensive transthoracic echocardiography using commercially available iE33 instruments (Philips Medical Systems, Koninklijke, Netherlands). Standard echocardiographic views were used to obtain M-mode, two-dimensional (2D) and Doppler measurements, according to the recommendations of the American Society of Echocardiography [9]. LVEF was measured via a modified biplane Simpson's method from apical four- and two-chamber views. The left ventricular (LV) and left atrial (LA) dimensions and wall thickness were obtained in the parasternal long axis view with 2D methods, and the LA phasic volumes (maximal, minimal and precontraction LA volume when the AF patients were in sinus rhythm) were obtained from the four- and two-chamber views using the biplane discs method. The LA volume index was defined as LA volume divided by the patient's body surface area. The mitral inflow velocities were recorded by standard pulsed-wave Doppler, with the sample volume placed at the tip of the mitral valve leaflets in the apical four-chamber view. Tissue Doppler-derived peak LV relaxation velocities were obtained from the lateral and septal corners of the mitral valve annulus during the early (Ea) and late (Aa) diastolic phases of the cardiac cycle, at a sweep speed of 100mm/s. E/e’ was calculated as E divided by the average of the septal and lateral Ea velocities. The echocardiographic studies were performed by experienced sonographers, and the investigators were blinded to the incidence of AF recurrence.

2DSTE

GLAS measurements were performed offline by analysis of grey-scale images (four- and two-chamber views) using commercially available software (TomTec Imaging Systems GmbH, Unterschleissheim, Germany). The endocardial border of the LA wall was traced manually in the end-systolic frame, and an additional epicardial line was generated automatically by the software, which created a region of interest throughout four or five cardiac cycles. The accuracy of the region of interest was verified manually, and adjusted if necessary. The software divided the LA myocardium into six segments, and generated LA longitudinal deformation curves (Figure 1A). We used the onset of the P wave as the reference point for patients in sinus rhythm, and the onset of the QRS wave was used for patients in AF rhythm. The software calculated the average strain values for six segments in the four- and two-chamber views, and the average values of the four- and two-chamber views were calculated as GLAS. In the sinus rhythm group, we measured LA positive peak strain during ventricular systole, and LA negative peak strain during LA systole. The total strain (GLAS) was calculated using the following equation: positive peak strain minus negative peak strain. In the AF rhythm group, atrial contractility disappeared during AF, and the peak negative strain was 0. GLAS was identified as the peak positive strain value during ventricular systole (Figure 1B).



Figure 1


Figure 1. 

Measurements of global left atrial longitudinal strain (GLAS) by two-dimensional speckle tracking echocardiography. A. We identified the left atrial peak negative strain, the peak positive strain, the sum of these values and GLAS in sinus rhythm AF patients. B. In atrial fibrillation rhythm patients, we used the onset of the QRS wave as the reference point, and GLAS was identified as the peak positive strain value during ventricular systole.

Zoom

Electrophysiological study and catheter ablation procedure

All patients underwent pulmonary vein isolation as previously described [10, 11]. Briefly, antiarrhythmic agents were discontinued for at least five half-lives (except for amiodarone, which was stopped for at least 4 or 5 months), and oral anticoagulation was discontinued 3 days before AF ablation. The endpoint of the circumferential pulmonary vein isolation was complete disconnection of the pulmonary vein, resulting in electrical isolation of the vessel.

Follow-up

All patients were monitored by 12-lead electrocardiography and 24-hour Holter recording at 3, 6, and 12 months after AF ablation. Each outpatient who developed symptoms suggestive of AF (fatigue, dizziness, palpitations, nausea, etc.) was advised to undergo immediate electrocardiography monitoring or 24-hour Holter recording. Transient episodes of AF recurrence within the first 3 months after the ablation was defined as the blanking period. AF recurrence was defined as the presence of an irregular pulse or AF on rhythm monitoring, or as AF persistence requiring drug therapy for maintaining sinus rhythm after the blanking period.

Intra- and interobserver variability

Intraclass correlation coefficients were calculated to quantify the intraobserver and interobserver variability of GLAS in 15 randomly selected patients, measured first by one investigator, and then repeated twice by two investigators; the two investigators were blinded to each other's data and the incidence of AF recurrence.

Statistical analysis

Continuous variables are expressed as means±standard deviations if normally distributed. Discrete variables are described as counts with percentages. Comparisons between the recurrent AF group and maintenance of sinus rhythm (MSR) group were performed with a non-parametric test for continuous variables. The χ2 test or Fisher's exact test was used to analyse categorical data. The Cox proportional-hazards regression model was used to assess the risk of recurrent AF associated with decreased GLAS, and the covariate selection for model entry was based on clinical experience. The receiver operating characteristic (ROC) curve analyses were compared, and the optimal cut-off values with the greatest sensitivity and specificity were identified as having greater prediction accuracy. Statistical analyses were performed using SPSS, version 17.0.2 (SPSS, Inc., Chicago, IL, USA) and MedCalc, version 11.4.1.0 (MedCalc Software, Mariakerke, Belgium). All P values were two-sided, and a P value<0.05 was considered statistically significant.

Results
Clinical characteristics and echocardiographic variables

The baseline clinical and echocardiographic characteristics of the patients are summarized in Table 1. Of the 115 patients, 62 had persistent AF and 53 had paroxysmal AF (18 patients with paroxysmal AF showed AF rhythm during examination) before catheter ablation. There was no significant difference between the persistent and paroxysmal AF groups with respect to clinical characteristics, LVEF, E/e’, LA maximal volume index (LAVImax) and LV mass index. However, patients with persistent AF had significantly larger LA dimensions and a lower GLAS than patients with paroxysmal AF (all P <0.001).

Comparison of strain and echocardiographic variables

During the 12-month follow-up period after catheter ablation, 37 of 115 patients (32.2%) had recurrent AF: 22 patients (35.5%) in the persistent AF group (Table 2) and 15 patients (28.3%) in the paroxysmal AF group (Table 2). There were no significant differences in LV and LA diameters, LV mass index, LVEF and E/e’ between the two AF populations in the MSR and AF recurrence groups. In both populations, however, baseline pro-B-type natriuretic peptide (Pro-BNP) concentrations were significantly higher, and GLAS was more impaired in the AF recurrence group (all P <0.05). Regarding the persistent AF population, the recurrent AF group had a significantly larger LAVImax than the MSR group (P =0.001); in the paroxysmal AF population, however, LA peak negative strain and peak positive strain were worse in the recurrent AF group than in the MSR group (Table 2).

Predictors of AF recurrence

The univariate and multivariable Cox proportional-hazards analyses of the potential predictors of rhythm outcome after catheter ablation during the 12-month follow-up period are shown in Table 3 (for the persistent AF population) and Table 4 (for the paroxysmal AF population). In our cohort, the reduction in GLAS was the only independent predictor of recurrent AF in both the persistent AF population (hazard ratio: 0.81, 95% confidence interval [CI]: 0.71–0.93; P =0.004) and the paroxysmal AF population (hazard ratio: 0.79, 95% CI: 0.67–0.96; P =0.01), after adjustment for age, duration of AF, CHADS2 (Cardiac failure, Hypertension, Age, Diabetes, Stroke [doubled]) score, systolic blood pressure, LVEF, LAVImax, heart rate, Pro-BNP concentration and LA peak positive strain. In the comparison of the ROC curve analyses, the area under the ROC curve (AUC) for GLAS was greater than that for Pro-BNP concentration and LAVImax for both AF populations (Figure 2A and B). Regarding persistent AF, the cut-off value was 23.6% for predicting MSR after catheter ablation, with a sensitivity of 98% and a specificity of 58%; regarding paroxysmal AF, the cut-off value was 24.3% for predicting AF recurrence, with a sensitivity of 97% and a specificity of 86%.



Figure 2


Figure 2. 

Receiver operating characteristic (ROC) curves for predicting maintenance of sinus rhythm (MSR) during 12 months of follow-up. A. Patients with persistent atrial fibrillation. B. Patients with paroxysmal atrial fibrillation. The area under the ROC curve for global left atrial longitudinal strain (GLAS) was greater than that for left atrial maximal volume index (LAVImax) and pro-brain natriuretic peptide (Pro-BNP) concentration (P <0.05 versus GLAS).

Zoom

The intraobserver intraclass correlation coefficient for GLAS among patients with paroxysmal AF was 0.91 (95% CI: 0.75–0.97; P <0.001), and among those with persistent AF was 0.85 (95% CI: 0.67–0.96; P <0.001). The interobserver intraclass correlation coefficient for GLAS among patients with paroxysmal AF was 0.87 (95% CI: 0.60–0.94; P <0.001), and among those with persistent AF was 0.79 (95% CI: 0.41–0.93; P =0.002).

Discussion

Our main findings were as follows: impaired baseline GLAS is an independent predictor of a high risk of recurrent AF after catheter ablation in both persistent and paroxysmal AF; and LA deformation capacity measured by 2DSTE provides a comprehensive assessment of atrial function, and may be more helpful for identifying abnormal atrial substrates than conventional echocardiographic variables or demographic variables.

Predictors of recurrent AF

Several studies have shown that good predictors of catheter ablation success include young age, short duration of AF, paroxysmal AF and normal LA size and volume [5, 12]. Consistent with these results, our study demonstrated that LAVImax was associated with recurrent AF in the univariate Cox proportional-hazard analysis of patients with persistent AF. However, this result was not statistically significant in the multivariable analysis.

Recently, an increasing amount of literature evaluating atrial strain has shown its prognostic significance for predicting success rates after AF ablation or cardioversion [8, 13, 14]. Our sample finally confirmed that GLAS was an independent predictor of recurrent AF in the paroxysmal and persistent populations when they underwent first AF ablation. However, age, duration of AF, atrial diameter and volume, and other baseline clinical and echocardiographic characteristics did not predict MSR.

Usefulness of LA strain for predicting recurrent AF

Accumulating evidence from studies has demonstrated the significant prognostic value of LA myocardial deformation for identifying patients at high risk of recurrent AF after ablation [13, 15]. Hwang et al. [14] and Morris et al. [15] measured LA strain by 2DSTE in patients with 100% paroxysmal AF, and reported that the average values of LA systolic strain for each segment were strongly associated with recurrent AF after catheter ablation. Schneider et al. [16] demonstrated that regional LA strain and strain rate were the best predictors of MSR using tissue Doppler imaging, during a 3-month follow-up. Mirza et al. [8] also reported that LA lateral strain was the only independent predictor of recurrent AF for paroxysmal and persistent AF patients, during an 18-month follow-up.

Overall, our results corroborate the above studies; however, we studied a population composed of patients who exhibited both paroxysmal and persistent AF, with common co-morbidities. We performed transthoracic echocardiography in both sinus rhythm and AF rhythm. Furthermore, we analysed GLAS using 2DSTE. Compared with tissue Doppler imaging-based deformation imaging, 2DSTE appears to have overcome some of its limitations, such as myocardial translational motion and variable reproducibility [6]. The duration of follow-up in our study was more than 3 months, because the transient episodes of arrhythmia recurrence within the 90 days after catheter ablation were not counted as AF recurrence because of the irritability of the atria immediately after catheter ablation [17]. Hence, our study design was more comprehensive and rigorous, which confirms and expands these previous observations, by demonstrating the usefulness of GLAS regarding the prognostic stratification of AF recurrence after catheter ablation.

Atrial deformation variables

2DSTE was developed as an angle-independent, innovative method that provides insight into myocardial mechanics. Our study demonstrates that the prognostic significance of GLAS is superior to the other echocardiographic and clinical variables in patients with paroxysmal or persistent AF after catheter ablation. One might postulate that a decline in GLAS may represent the presence of subclinical myocardial damage and abnormal atrial substrate. Recently, Kuppahally et al. have demonstrated that LA strain was strongly correlated with LA structural remodelling observed on magnetic resonance imaging, and LA fibrosis found in histopathology results [18]. Thus, GLAS is a potential non-invasive surrogate marker of LA myocardial performance that might be of great value for preablation patient selection in routine clinical practice.

Certain patients with paroxysmal AF were in AF rhythm during the echocardiographic examination, and AF frequently affects LA contractile function. In addition, LA contractile function can be more impaired than reservoir function after the termination of AF, because of LV stunning. Therefore, we chose the variable of peak positive strain rather than negative strain for comparison with GLAS; however, this did not significantly predict AF recurrence according to the multivariable analysis. Correspondingly, we found that LA peak negative and positive strain were not better correlated with AF recurrence than GLAS after catheter ablation, per a ROC analysis (paroxysmal AF population: peak positive strain, AUC: 0.68 vs. 0.94; peak negative strain, AUC: 0.76 vs. 0.94).

GLAS was measured during ventricular systole to reflect LA reservoir function, which not only reflects the distensibility of the LA wall, but is related to atrial fibrosis and chamber stiffness. Consistent with Motoki et al. [19], our study results revealed that LA reservoir function was a more sensitive variable for predicting the success of AF ablation.

Clinical implications

Global LA deformation imaging shows satisfactory feasibility and reproducibility as a non-invasive method for assessing patients at high risk of AF recurrence after catheter ablation, and might be useful for evaluating questionable candidates for AF ablation. LA strain imaging is also non-invasive, and is relatively readily available compared with other imaging methods; therefore, it can be widely used in clinical practice.

Study limitations

First, although specking tracking software is designed for analysing the ventricles, we used it for atrial deformation analysis. Second, we set the referent point to the onset of the P wave in patients with sinus rhythm, and to the onset of the QRS wave in patients with AF rhythm; certain subtle differences might be present in these two analytical methods. Third, patients cannot be monitored continuously throughout the follow-up period; consequently, asymptomatic episodes of AF might not have been detected, leading to an underestimation of the true rate of AF recurrence. Fourth, LA strain variables might have been influenced by preload and afterload conditions, because of differences in medical therapy, etc. Finally, none of the patients used medications to control their heart rate during the echocardiographic examination, which might have affected their myocardium deformation capability.

Conclusion

In both AF populations, impaired baseline GLAS values measured by STE imaging appeared to be associated with a higher recurrence rate after AF ablation during 12 months of follow-up. The assessment of LA myocardial deformation capabilities before ablation might help to guide the appropriate selection of treatment strategies, and thereby improve therapeutic effectiveness.

Funding

This study was partially supported by a research grant from the Science & Technology Committee of Shanghai Municipal Government, People's Republic of China (Grant No. 134119a5801).

Disclosure of interest

The authors declare that they have no competing interest.

References

Cappato R., Calkins H., Chen S.A., and al. Updated worldwide survey on the methods, efficacy, and safety of catheter ablation for human atrial fibrillation Circ Arrhythm Electrophysiol 2010 ;  3 : 32-38 [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]
Hof I., Chilukuri K., Arbab-Zadeh A., and al. Does left atrial volume and pulmonary venous anatomy predict the outcome of catheter ablation of atrial fibrillation? J Cardiovasc Electrophysiol 2009 ;  20 : 1005-1010 [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]
Oral H., Knight B.P., Tada H., and al. Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation Circulation 2002 ;  105 : 1077-1081 [cross-ref]
Cameli M., Caputo M., Mondillo S., and al. Feasibility and reference values of left atrial longitudinal strain imaging by two-dimensional speckle tracking Cardiovasc Ultrasound 2009 ;  7 : 6 [cross-ref]
Kusunose K., Motoki H., Popovic Z.B., Thomas J.D., Klein A.L., Marwick T.H. Independent association of left atrial function with exercise capacity in patients with preserved ejection fraction Heart 2012 ;  98 : 1311-1317 [cross-ref]
Mirza M., Caracciolo G., Khan U., and al. Left atrial reservoir function predicts atrial fibrillation recurrence after catheter ablation: a two-dimensional speckle strain study J Interv Card Electrophysiol 2011 ;  31 : 197-206 [cross-ref]
Lang R.M., Bierig M., Devereux R.B., and al. Recommendations for chamber quantification: a report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology J Am Soc Echocardiogr 2005 ;  18 : 1440-1463 [inter-ref]
Haissaguerre M., Jais P., Shah D.C., and al. Catheter ablation of chronic atrial fibrillation targeting the reinitiating triggers J Cardiovasc Electrophysiol 2000 ;  11 : 2-10 [cross-ref]
Kanj M.H., Wazni O.M., Natale A. How to do circular mapping catheter-guided pulmonary vein antrum isolation: the Cleveland Clinic approach Heart Rhythm 2006 ;  3 : 866-869 [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]
Hammerstingl C., Schwekendiek M., Momcilovic D., and al. Left atrial deformation imaging with ultrasound based two-dimensional speckle-tracking predicts the rate of recurrence of paroxysmal and persistent atrial fibrillation after successful ablation procedures J Cardiovasc Electrophysiol 2012 ;  23 : 247-255 [cross-ref]
Hwang H.J., Choi E.Y., Rhee S.J., and al. Left atrial strain as predictor of successful outcomes in catheter ablation for atrial fibrillation: a two-dimensional myocardial imaging study J Interv Card Electrophysiol 2009 ;  26 : 127-132 [cross-ref]
Morris D.A., Parwani A., Huemer M., and al. Clinical significance of the assessment of the systolic and diastolic myocardial function of the left atrium in patients with paroxysmal atrial fibrillation and low CHADS(2) index treated with catheter ablation therapy Am J Cardiol 2013 ;  111 : 1002-1011 [inter-ref]
Schneider C., Malisius R., Krause K., and al. Strain rate imaging for functional quantification of the left atrium: atrial deformation predicts the maintenance of sinus rhythm after catheter ablation of atrial fibrillation Eur Heart J 2008 ;  29 : 1397-1409 [cross-ref]
Calkins H., Reynolds M.R., Spector P., and al. Treatment of atrial fibrillation with antiarrhythmic drugs or radiofrequency ablation: two systematic literature reviews and meta-analyses Circ Arrhythm Electrophysiol 2009 ;  2 : 349-361 [cross-ref]
Kuppahally S.S., Akoum N., Badger T.J., and al. Echocardiographic left atrial reverse remodeling after catheter ablation of atrial fibrillation is predicted by preablation delayed enhancement of left atrium by magnetic resonance imaging Am Heart J 2010 ;  160 : 877-884 [inter-ref]
Motoki H., Negishi K., Kusunose K., and al. Global left atrial strain in the prediction of sinus rhythm maintenance after catheter ablation for atrial fibrillation J Am Soc Echocardiogr 2014 ;  27 : 1184-1192 [inter-ref]



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