BOSTON, MASSACHUSETTS. Atrial fibrillation (AF) is the most common cardiac arrhythmia and its prevalence in the general population is increasing rapidly. There is substantial evidence that AF is associated with systemic inflammation as measured via C-reactive protein (CRP) level; however, until now it has not been clear whether inflammation causes AF or AF results in inflammation. Researchers at Harvard Medical School now provide conclusive evidence that systemic inflammation precedes the development of AF in women. Their study involved 24,734 women who were part of the ongoing Women's Health Study (WHS) begun in 1993. At baseline, the participants (female health professionals between the ages of 49 and 59 years) completed health questionnaires and had blood samples drawn for analysis of three biomarkers for inflammation – CRP, slCAM-1 and fibrinogen. NOTE: slCAM-1 is soluble intercellular adhesion molecule-1, an inflammatory molecule associated with atherosclerosis.

During the 14-year follow-up period, 747 women developed AF (94% lone AF). The researchers found a clear correlation between elevated inflammation markers at baseline and the risk of developing AF. Assigning 1 point each for CRP level above 3.4 mg/L (0.34 mg/dL), slCAM-1 level above 373 ng/mL, and fibrinogen level above 382 mg/dL, the researchers observed that women with 1 point had a 22% increased risk of developing AF compared to women with 0 points (none of the inflammation markers above the cut-off points). Women with a 2-point score had a 32% increased risk, and those with a 3-point score had a 59% increased risk after adjusting for possible confounding variables including smoking, blood pressure, body mass index, diabetes, hypercholesterolemia, exercise, alcohol consumption, and race/ethnicity. The actual number of newly diagnosed afibbers per 1000 person-years was 1.66 for an inflammation score of 0, 2.2 for a score of 1, 2.73 for a score of 2, and 3.25 for a score of 3.

The researchers conclude that, "markers of inflammation were independently associated with incident AF in initially healthy, middle-aged women, even after controlling for traditional risk factors. These findings suggest that inflammation may be involved in the pathogenesis of AF."
Conen, D, et al. A multimarker approach to assess the influence of inflammation on the incidence of atrial fibrillation in women. European Heart Journal, May 25, 2010 [Epub ahead of print]

Editor's comment: There is overwhelming evidence of an association between systemic inflammation and atrial fibrillation. The Harvard study clearly supports the hypothesis that inflammation causes AF rather than vice versa. Although this study in no way proves that existing afib can be reduced or eliminated by eliminating systemic inflammation, it certainly would be advisable to do so, preferably through the use of such natural anti-inflammatories as curcumin, bromelain, ginger, beta-sitosterol, boswellia, fish oil, Zyflamend or Moducare.