3.1 Study selection
The literature search resulted in 1054 records, and 3 more records were identified through hand search of reference list of those articles. Excluding 449 duplicated records, there are 604 remaining records, in which 567 were not related to the topic. After reading the full texts of the 37 remaining articles, 29 articles were excluded because of a lack of EAT measurement (n=11), cardiac surgery (n=13), atrial fibrillation occurrence (n=2) or comparison (n=3). Finally, the findings of the 10 studies published in 8 articles with 3 sub-groups were enrolled in the study (Fig. 1).