Relation of Proinflammatory Activity of Epicardial Adipose Tissue to the Occurrence of Atrial Fibrillation

Epicardial adipose tissue (EAT) contains abundant ganglionated plexi that might contribute to the occurrence of atrial fibrillation (AF). Maximal standardized uptake value (SUV) of 18-fluorodeoxyglucose (FDG)-positron emission tomography (PET) reflects glucose metabolism of the tissue. It has also been shown that FDG-PET is proportional to macrophage density. We examined EAT inflammatory activity using FDG-PET/computerized tomography in patients with AF and in controls. Retrospective analysis of patients who underwent FDG-PET/computerized tomography was performed. About 21 consecutive patients with confirmed history of AF and 21 non-AF control group matched for age, gender, and body mass index (BMI) were included. SUV was measured in fat adjacent to the roof of left atrium, right ventricle, atrioventricular groove, and left main artery. Additionally SUV was measured in subcutaneous fat and visceral thoracic fat. In both groups, associations of SUV with gender, age, BMI, and serum glucose were further analyzed. EAT SUV measured near the roof of left atrium, atrioventricular groove, and left main artery was significantly greater in patients with AF than in control group (1.66 ± 0.36 vs 1.23 ± 0.32, p = 0.00015; 2.07 ± 0.50 vs 1.51 ± 0.24, p = 0.00003; and 1.95 ± 0.48 vs 1.52 ± 0.26, p = 0.0007, respectively). In addition, EAT SUV was significantly greater than subcutaneous and visceral thoracic fat for patients with AF and controls. EAT SUV was not related to gender, age, BMI, or serum glucose. In conclusion, inflammatory activity of EAT reflected by SUV is higher in patients with AF than that in controls. Inflammatory activity of EAT adjacent to left atrium, atrioventricular groove, and left main artery is greater than in subcutaneous or visceral thoracic tissue.