ABC | Volume 112, Nº5, May 2019

Original Article Left Atrial Stiffness: A Predictor of Atrial Fibrillation Recurrence after Radiofrequency Catheter Ablation - A Systematic Review and Meta‑Analysis Eduardo Thadeu de Oliveira Correia , Letícia Mara dos Santos Barbetta , Othon Moura Pereira da Silv a, Evandro Tinoco Mesquit a Universidade Federal Fluminense (UFF), Niterói, RJ – Brazil Mailing Address: Eduardo Thadeu de Oliveira Correia • Av. Marquês do Paraná, 303. Postal Code 24220-000, Centro, Niterói, RJ – Brazil E-mail: etocorreia@outlook.com, etocorreiamed@gmail.com Manuscript received May 30, 2018, revised manuscript August 20, 2019, accepted September 05, 2018 DOI: 10.5935/abc.20190040 Abstract Background: Radiofrequency catheter ablation (RFCA) is a standard procedure for patients with atrial fibrillation (AF) not responsive to previous treatments, that has been increasingly considered as a first-line therapy. In this context, perioperative screening for risk factors has become important. A previous study showed that a high left atrial (LA) pressure is associated with AF recurrence after ablation, which may be secondary to a stiff left atrium. Objective: To investigate, through a systematic review and meta-analysis, if LA stiffness could be a predictor of AF recurrence after RFCA, and to discuss its clinical use. Methods: The meta-analysis followed the MOOSE recommendations. The search was performed in MEDLINE and Cochrane Central Register of Controlled Trials databases, until March 2018. Two authors performed screening, data extraction and quality assessment of the studies. Results: All studies were graded with good quality. A funnel plot was constructed, which did not show any publication bias. Four prospective observational studies were included in the systematic review and 3 of them in the meta-analysis. Statistical significance was defined at p value < 0.05. LA stiffness was a strong independent predictor of AF recurrence after RFCA (HR = 3.55, 95% CI 1.75-4.73, p = 0.0002). Conclusion: A non-invasive assessment of LA stiffness prior to ablation can be used as a potential screening factor to select or to closely follow patients with higher risks of AF recurrence and development of the stiff LA syndrome. (Arq Bras Cardiol. 2019; 112(5):501-508) Keywords: Atrial Fibrillation; Catheter Ablation/methods; Heart Atria; Tachycardia, Paroxysmal; Metanalysis. Introduction Radiofrequency catheter ablation (RFCA) is a standard procedure for the treatment of atrial fibrillation (AF) in patients not responsive to previous treatments. 1 However, growing evidence has shown lower rates of AF recurrence and AF burden in patients with paroxysmal AF that were submitted to ablation as a first-line therapy option. 2 In addition to that, progression from paroxysmal AF to persistent AF appears to be delayed by early catheter ablation of AF. 2 Therefore, catheter ablation has been increasingly considered as a first-line therapy option, which makes it more important to use screening factors to closely follow patients with higher risk of AF recurrence and post-procedural complications. Recently, the importance of studying left atrial (LA) stiffness has been growing exponentially, since it has been linked to the stiff left atrial syndrome (SLAS), a severe consequence of RFCA. 3 Moreover, a previous study 4 showed that an increase in LA pressure is associated with AF recurrence after ablation. Since a high LA pressure may be secondary to an increase in LA stiffness, 5 LA stiffness itself could be a predictor of AF recurrence after RFCA and, thereby promote a closer follow-up of patients at higher risk of AF recurrence and development of the SLAS. However, no systematic review or meta-analysis has been published to investigate this relationship, although these studies could provide the strongest and the highest quality of evidence. Therefore, this systematic review and meta-analysis aims to investigate if LA stiffness itself could be a predictor of AF recurrence after RFCA and discusses the clinical usefulness of this new predictor. 6 Methods A systematic review was performed using the criteria established by the Meta-analysis of Observational studies in the Epidemiology Group (MOOSE). Search strategy Two investigators (ETOC, ETM) searched the MEDLINE and the Cochrane Central Register of Controlled Trials databases, 501