Fehmi Keçe

Left Atrial Box Surface Ratio and AF-Recurrence 167 8 8.2.5 Statistical Analysis Clinical, echocardiographic, and ablation data were prospectively collected in the departmental Cardiology Information System (EPD-Vision®, Leiden University Medical Centre, Leiden, The Netherlands) and retrospectively analysed. Continuous variables were expressed asmean ± standard deviation or median (interquartile range (IQR)) and compared by an unpaired t-test or Mann-Whitney U-test when indicated. Categorical variables were presented as numbers and percentages, and compared by the chi-square or Fisher’s exact test when appropriate. Kaplan Meier survival curves were constructed to compare the AF- free survival between the 2 groups. Multivariable Cox proportional regression analysis was performed to detect any independent significant predictors of AF/AT recurrence reported as hazard ratio (HR) with 95% confidence interval (CI). Previously reported predictors of AF recurrence (17) after catheter ablation were tested in the univariate model. Variables with a p < 0.1 in the univariate analyses were included in the multivariate analyses using the ‘enter’ method. P < 0.05 was considered as significant. All analyses were performed with the SPSS version 23 statistics software package (SPSS, Chicago, IL).