2.4 Statistical analysis
Statistical analysis of all data was performed using SPSS 25. 0. The continuous variables were tested for normality using the Shapiro-Wilks test. When the continuous variables were conformed to normal distributions, they were expressed as mean±SD, and the date with skewed distributions were expressed as medians with 25% and 75% interquartile ranges. Categorical variables were expressed as numbers with percentages. The continuous variables conforming to normal distribution between three groups were compared by F-test or Welch’s test. When at least one of three groups of continuous variables conforms to skewed distribution, the kruskal-Wallis test was used. Then, we performed multiple comparisons between groups. Categorical variables between three groups were compared by Chi-square test. Pearson and Spearman Correlation Coefficient were used to determine the correlation between EAT thickness and LAD, as well as the correlation between EAT thickness and left atrial phasic function in patients with AF. Intra-class correlation coefficient (ICC) was used to test the reproducibility of measurement of EAT thickness and left atrial phasic function parameters within and between operators. For all tests, a p<0. 05 was defined as statistically significant.