White blood cell count predicts AF

BOSTON, MASSACHUSETTS. Numerous studies have found a clear association between inflammation and atrial fibrillation (AF). Several of these studies measured level of C-reactive protein (CRP), a powerful marker of systemic inflammation, and concluded that CRP levels are elevated in paroxysmal afibbers, and further elevated in persistent and permanent (long-standing persistent) afibbers. What is still not entirely clear is whether the observed correlation means that inflammation is a cause of AF or that AF is a cause of inflammation. Now a group of American, Dutch and German researchers weigh in with new research that supports the hypothesis that inflammation is a cause of AF.

Their study involved 936 participants in the Framingham Heart Study originally enrolled in 1948. At the routine follow-up examination in 1988, the average age of the cohort was 76 years and 61% were women. Ten percent had experienced a prior heart attack, 10% were current smokers, and 54% were on anti-hypertensive medications. The average (median) white blood cell (WBC) count was 6.4 x 109/L. An elevated WBC count is the most commonly used marker for systemic inflammation.

During a 5-year follow-up, 82 study participants (9%) developed AF or flutter. The incidence was 5% among participants with a WBC count less than 5.9 x 109/L and 15% among those with a WBC count greater than 7.3 x 109/L. The association between elevated WBC count and increased risk of AF did not change after adjusting for previous heart attack, smoking, heart failure, and known risk factors for AF.

The researchers conclude that an elevated WBC count is associated with an increased future risk of AF and speculate that inflammation causes modification of heart tissue (substrate) through electrical and structural remodeling of the atria. They recommend further studies to confirm their findings and to conclusively determine whether inflammation is a risk factor or a risk marker for AF.
Rienstra, M, et al. White blood cell count and risk of incident atrial fibrillation. American Journal of Cardiology, 2012 [Epub ahead of print]

Editorís comment: This exploratory study lends credence to the hypothesis that systemic inflammation is associated with an increased risk of developing AF. It does not involve a huge leap of faith to also hypothesize that inflammation is involved in the maintenance and progression of already established AF. Thus, it would seem prudent for afibbers with elevated WBC or CRP levels to take steps to eliminate, or at least reduce, their systemic inflammation. Powerful natural anti-inflammatories such as fish oils, vitamin C, curcumin, Zyflamend, Boswellia, beta-sitosterol, and pycnogenol can help achieve this goal.