Prospective assessment of cytokine IL-15 activity in patients with refractory atrial fibrillation episodes

Aims: Inflammatory state is considered a risk factor of atrial fibrillation (AF) occurrence. The aim of this study was a prospective evaluation of the inflammation parameters in patients with different forms of AF without structural heart disease. Methods and results: One hundred fifty-eight patients with paroxysmal/persistent AF (87; 55.1% men, mean age 65.8 +/- 9.6 years) without structural heart disease were enrolled in the study. Inflammatory parameters: WBC, ESR, hs-CRP, IL-6, IL-15 and TNF-alpha were measured at baseline and after one year follow-up. Despite frequent AF episodes median values of WBC, ESR and C-reactive protein at baseline and after follow up were within normal ranges. There were no significant differences between WBC, ESR and hs-CRP regarding AF types. In patients who developed permanent AF form (n = 14) hs-CRP concentrations were higher at baseline: 0.35 (IQR1: 0.09 IQR: 0.61) vs 0.15 (IQR1: 0.07 IQR: 0.29), p < 0.01. Nevertheless, after one year's observation these differences were not significant. Among all cytokines were studied only IL-15 was significantly correlated with the number of AF episodes (r = 0.26), mean (IQ1-1Q3): 10 (3-30) vs 60 (50-100), p = 0.00681. Conclusion: Basic inflammatory markers were not changed in patients with refractory atrial fibrillation episodes in prospective one year's observation. Only cytokine IL-15 was correlated to numbers of AF episodes. It's potential role as a marker of arrhythmia deserves further evaluation. (C) 2015 Elsevier Ltd. All rights reserved.