ABC | Volume 114, Nº4, April 2020

Original Article Correia et al. CA lesions and AF recurrence - a meta-analysis Arq Bras Cardiol. 2020; 114(4):627-635 Figure 2 – Forest plot showing that the extent of left atrial scarring is associated with less atrial fibrillation recurrence after catheter ablation. CI: confidence interval; IV: inverse variance 1.0455 1.05 [0.33, 1.76] 0.30 [–0.39, 0.99] 0.54 [0.18, 0.90] 0.36 [–0.09, 0.82] 0.52 [0.27, 0.76] AF recurrence –2 –1 0 1 2 No recurrence 0.364 0.3519 0.1837 0.2321 29.1% 100.0% 2008 2009 2010 2015 46.4% 12.7% 11.8% 0.3028 0.54 0.365 McGann et al. 2008 Peters et al. 2009 Badger et al. 2010 Parmar et al. 2015 Total (95% Cl) Heterogeneity: Chi 2 = 2.92, df = 3 (p = 0.40); I 2 = 0% Test for overall effect: Z = 4.15 (p < 0.0001) Study or Subgroup Std. Mean Difference Std. Mean Difference Std. Mean Difference SE Weight IV, Fixed, 95% Cl IV, Fixed, 95% Cl Year Figure 3 – Funnel plot showing no publication bias. SE (SMD) 0 0.1 0.2 0.3 0.4 0.5 –2 –1 0 1 2 SMD multicenter study, which, in patients with persistent AF, compared CPVI alone, CPVI plus linear ablation across the LA roof and mitral valve isthmus, and CPVI plus ablation of complex fractionated electrograms. No reduction was found in the recurrence of AF when additional strategies beyond CPVI were performed. 36 The DECAAF study showed that LA fibrosis visualized by LGE-MRI was a strong predictor of ablation outcome, and the more ablation-induced scarring overlapped fibrotic tissue, the better the outcome. 37 Accordingly, the DECAAF II study will randomize patients with persistent AF to receive either conventional PVI ablation or PVI guided by LGE-MRI. 38 Future studies The increased use of CA for AF correction in clinical practice requires better strategies to reduce post procedural failures. It is necessary to conduct randomized controlled trials that compare driver-guided CA by electroanatomic mapping with traditional ablation methods. Moreover, it is important to standardize LGE-MRI to detect LA scars in order to guarantee its reproducibility. In addition to that, developing real-time MRI on a larger scale might reduce its costs, making it possible to use in the future. Limitations Although the present systematic review and meta-analysis provides a significant increase in the number of patients analyzed, the number of patients included is limited. Moreover, only four studies were included in the quantitative analysis, and all of themwere observational studies. Although LGE-MRI is feasible to detect post-ablation atrial scar, its reproducibility needs to be further studied. Conclusion The present review shows that the extent of post-ablation LA scars is possibly associated with less AF recurrence after 632