ABC | Volume 112, Nº5, May 2019

Original Article Correia et al LA stiffness and AF recurrence - a meta-analysis Arq Bras Cardiol. 2019; 112(5):501-508 Figure 3 – Funnel plot showing no publication. 0 0.1 0.2 0.3 0.4 0.5 0.02 0.1 1 10 50 Hazard Ratio SE (log[Hazard Ratio]) longitudinal deformation of the LA and the movement of the shared mitral annulus and the adjacent ventricle, information from LV longitudinal strain could be used to estimate LA stiffness. 9 With this non-invasive measurement by a simple ECG, LA stiffness could be a potential new screening factor in the preoperative routine. Future studies The present review shows a need for further studies to better understand the relation between LA stiffness and AF. First, an increase in the number of studies and in total sample could increase reliability of results. Also, a development of a standard non-invasive LA stiffness index would contribute for screening of patients which would not benefit from the ablation. Finally, further studies are also needed to investigate if LA stiffness is a real risk factor that could lead to AF development and propagation or if it is just a consequence of AF. Limitations The present review has some limitations. First, in the quantitative analysis only three observational studies were included. Also, the I² test showed a high heterogeneity (p = 0.05, I² = 67%), although the overall outcome remained the same after excluding the study of Khurram et al., 13 which caused heterogeneity. This heterogeneity might be related to several factors. First, the study of Khurram et al. 13 took place in North America, while the other two studies were performed in Asia. Second, although all methods used for the measurement of LA stiffness were different between studies, the study by Khurram et al. 13 was the most varied among all in this sense, because it used cardiac magnetic resonance, and did not use ECG for diagnosing AF. Also, the study by Khurram et al. 13 had the shorter mean follow-up period of all studies. In addition to these limitations, although adjusted HRs from multivariate analysis were used to reduce the effect of confounding variables, they cannot exclude them completely. Conclusions The present review shows that LA stiffness is a strong predictor of AF recurrence after RFCA (HR = 3.55, 95% CI 1.75–4.73, p = 0.0002). Therefore, a standard non‑invasive LA stiffness measure, could be routinely used prior to AF ablation, tracking patients with higher chances of AF recurrence and development of the SLAS. Author contributions Conception and design of the research, acquisition of data, analysis and interpretation of the data, writing of the manuscript and critical revision of the manuscript for intellectual content: Correia ETO, Barbetta LMS, Silva OMP, Mesquita ET; statistical analysis: Correia ETO, Barbetta LMS. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. Ethics approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors. 506