3.7. Statistical analysis
Categorical values are expressed as absolute values and relative
frequencies. Continuous variables are expressed as mean ± SD. Tests for
significance were conducted using the unpaired t-test or nonparametric
test (Mann-Whitney U-test) for continuous variables and the chi-squared
test or Fisher’s exact test for categorical variables. When a continuous
LACV significantly differed between the two groups, receiver operating
characteristic analysis was performed to delineate the cut-off points.
Univariate and multivariate Cox proportional hazard models and logistic
regression analyses were used to determine the clinical factors that
were associated with AF recurrence and a slow LACV, respectively.
Survival rates free from atrial tachyarrhythmias were calculated using
the Kaplan–Meier method. Survival curves between groups were compared
with the two-sided Mantel–Haenszel (log-rank) test. All statistical
analyses were performed using commercial software (SPSS version 25 ®,
SPSS, Chicago, IL, USA), and statistical significance was defined as P
< 0 .05.