Prognostic impact of hs-CRP and IL-6 in patients with persistent atrial fibrillation treated with electrical cardioversion.

OBJECTIVE

The aim of this study was to assess the role of inflammatory processes in the development of atrial fibrillation (AF) and the prognostic impact of inflammatory markers in predicting long-term risk of AF recurrence after electrical cardioversion (CV).

METHODS

High-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) were measured in 56 patients with persistent AF (lasting mean 128 days (range 14-960), mean age 65 years (34-84)), 19 healthy volunteers and 19 patients with permanent AF. Patients with persistent AF underwent CV. Blood samples were taken prior to CV and after 1, 30 and 180 days.

RESULTS

The immediate success rate of CV was 88%, while the total recurrence rate after 180 days was 68%. Patients with permanent AF had significantly higher levels of hs-CRP and IL-6 than patients with persistent AF (p = 0.0011, p<0.001). Patients in sinus rhythm (SR) after 180 days had significantly lower baseline hs-CRP (1.25 mg/L (0.5-2.4) versus 2.0 mg/L (0.9-3.3), p<0.001) and IL-6 (1.96 pg/mL (1.35-2.7) versus 2.75 pg/mL (1.55-3.62), p<0.001) than patients with recurrent AF. Baseline IL-6 was the only independent predictor of recurrent AF (p = 0.04) in a multivariate Cox analysis. Patients in the lowest hs-CRP quartile (<0.8 mg/L) had significantly lower AF recurrence rates after 180 days (50% versus 74% in the other three quartiles combined; p = 0.0069).

CONCLUSION

Patients with AF had elevated levels of inflammatory markers. Low hs-CRP and IL-6 prior to CV are associated with a lower risk of AF recurrence after CV.