2.6 Statistical analysis
Continuous variables are
expressed as mean ± SD values or median, and categorical variables are
expressed as the number and percentage of patients. Student’st -test or Mann-Whitney U test was used, as appropriate, to
analyze between-group differences in continuous variables, and the
chi-square test was used to analyze between-group differences in
dichotomous variables unless the expected counts were < 5, in
which case Fisher’s exact test was used. Receiver operating
characteristic (ROC) curves were plotted to determine the cutoff values
of the ablation-related variables for prediction of gaps. The areas
under the curve (AUC) were compared by DeLong test. The ROC curves and
AUCs were analyzed with MedCalc ver. 16.4.1 (MedCalc Software,
Mariakerke, Belgium). All other statistical analyses were performed with
JMP 11 software (SAS Institute, Cary, NC). P < 0.05 was
considered statistically significant.