Fehmi Keçe

Left Atrial Box Surface Ratio and AF-Recurrence 171 8 mitral annulus was observed (p=0.266). The distance between the posterior line to the mitral annulus was also not significantly different in patients with and without documented atypical/ mitral isthmus dependent flutter (51±9 vs. 54±8 mm; p=0.236). Kaplan-Meier survival curves showed that patients with a larger box surface ratio had a lower incidence of AF/AT recurrence. The median survival (free from AT/AF) after the index LA box lesion was 8 months in the large box surface ratio group and 14 months in the small box surface ratio group (p=0.0324 by log- rank test; HR 0.57 [ CI 0.3086 – 1.058) (Figure 2). Table 3. Univariate and Multivariate Cox Proportional Regression Analyses for predictors of AF/ AT recurrence. Variables Univariate Multivariate Hazard ratio (95% confidence interval) P value Hazard ratio (95% confidence interval) P value Age 0.990 (0.961–1.021) 0.536 Female sex 0.716 (0.342–11.502) 0.377 BMI 1.012(0.936-1.094) 0.759 SR at admission 1.493(0.703-3.169) 0.297 Previous PVI 1.631 (0.859-3.096) 0.134 Additional Ablation 1.584 (0.719-3.490) 0.253 AF duration 1.003 (998-1.009) 0.245 CHA 2 DS 2 -VASc 0.961(0.744-1.240) 0.758 Distance posterior line to mitral annulus 0.992 (0.953-1.033) 0.705 Box lesion width 1.038 (0.978-1.101) 0.217 Box lesion height 0.999 (0.950-1.050) 0.968 Box lesion surface area 1.004 (0.938-1.074) 0.916 LA volume index 1.015 (1.000-1.031) 0.046 1 .007 (0.990-1.024) 0.427 Prior mitral valve surgery 2.263 (0.936–5.476) 0.070 2.903 (0.970–8.693) 0.057 Box surface ratio 0.850 (0.729–0.991) 0.038 0.812 (0.690–0.955) 0.012 AF indicates atrial fibrillation; BMI, body mass index; LA, left atrium; EF, ejection fraction; PVI, pulmonary vein isolation and SR, sinus rhythm. 8.3.6 Repeat procedures In 15 patients, a re-ablation was performed after the index box lesion isolation. In all patients, isolation of the pulmonary veins and of the box lesion was checked and/or an additional ablation was performed. Two patients underwent a His-ablation after permanent