The relevance of the association between inflammation and atrial fibrillation

Abstract Background The relevance of the association between inflammation and atrial fibrillation ( AF ) is not firmly established. The clinical importance is considerable because inflammation is usually not targeted as a treatment option, minimizing a probable benefit. Materials and methods We have used a case–control study with a Mendelian randomization rationale to assess whether proposed risk factors that have a genetic component and are readily detected in circulating blood are causally related to AF . The studied variables were C ‐reactive protein ( CRP ) and a representative of the chemokine system, the monocyte chemoattractant protein‐1 ( CCL 2). Results Plasma CRP and CCL 2 concentrations were significantly higher in AF patients than in the unaffected population. However, when segregated between paroxysmal and permanent, the difference for CRP was only observed in patients with a permanent condition. Plasma CCL 2 was raised in both subgroups. Confounding factors were carefully considered, and multivariable analyses revealed that circulating CCL 2 was significant and CRP was negligible to explain the presence of AF . The duration of the episode also bore a significant predictive value. Odd ratios for AF as a function of genotype did not differ from 1·0 for any of the individual CRP and CCL 2 polymorphisms, or any combinations. Conclusions Elevated plasma CRP concentration per se does not increase atrial fibrillation risk. Values obtained for CCL 2 suggest that inflammation is probably a consequence of AF . Our data also suggest that the effect of the duration of the episode should be further studied in the assessment of the actual role of inflammation.