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 study by Khurram et al., 13 160 patients from the original study were included in the analysis of the outcomes, and hence included in the present review. The study of Park et al. 12 analysed 1,038 patients, however only 334 patients had a structurally normal heart and were included in the analyses. Although Kawasaki et al. 10 analysed 137 subjects, only 109 patients underwent first ablation, and were included in the present review. Overall, 758 and 649 patients were included in our qualitative and quantitative analysis, respectively. The mean follow-up period ranged from10.4 to 33.8months. Studies used different techniques tomeasure LA stiffness, which are depicted in Table 1. All studies performed pulmonary vein isolation as ablation strategy and Holter monitoring for diagnosing AF. Also, three 10-12 of four studies used electrocardiogram (ECG) to perform the diagnosis. Khurram et al. 13 did not perform an ECG, although they also used 30-day event monitoring. Blanking period for AF recurrence post-RFCA lasted three months in two studies, 11,13 one month in one study, 10 and was not mentioned in the study by Park et al. 12 Characteristics from all included studies are summarized in Table 1. LA stiffness as a predictor of AF recurrence Two 11,13 of the four included studies found that LA stiffness was the most important predictor for recurrence of AF post‑ablation on a multivariate analysis, among several factors such as LA volume and persistent AF. Khurram et al. 13 observed that LA stiffness index was an independent predictor of AF ablation outcome (HR: 8.22; 95% CI: 3.54 to 19.11; p < 0.001). Besides that, 25% of patients (40 of 160) had AF recurrence after AF ablation during a follow-up period of 10.4 ± 7.6 months. Patients with AF recurrence had a higher LA stiffness index than those without recurrence. These findings are also confirmed by the study by Machino-Ohtsuka et al., 11 which also showed that the patients with recurrence (29%, 45 of 155) had a higher LA stiffness than those without recurrence during a follow-up period of 33.8 ± 12.2 months. In addition, the study also showed that a higher LA stiffness index was an independent predictor of recurrence of AF (HR 2.88; 95% CI 1.75 to 4.73, p < 0.001). Figure 1 – Flow diagram of the study selection. 62 records identified through databese searching: 57 in MEDLINE and 5 in Cochrane Central Register of Controlled Trials 60 records after duplicates were removed 60 records screened 5 full-text articles assessed for eligibility 4 studies included in the systematic-review 3 studies included in the meta-analysis 55 records excluded because they were unrelated to this meta-analysis 1 study excluded because the mean follow-up period was shorter than 6 months and only 20 subjects were included 504