Angiotensin II blockade, YKL-40 and maintenance of sinus rhythm after electrical cardioversion for atrial fibrillation.

High levels of the novel inflammatory marker YKL-40 have been demonstrated in inflammatory environments and in remodeling of the extracellular matrix. Both are key components in atrial wall remodeling in atrial fibrillation (AF). We studied the relation between rhythm outcome after electrical cardioversion (ECV) for persistent AF and serum levels of YKL-40. A secondary point of interest was a potential effect of the angiotensin receptor blocker candesartan on YKL-40 levels. In the Candesartan in the Prevention of Relapsing Atrial Fibrillation (CAPRAF) study, 171 patients with persistent AF were randomized to receive candesartan 8mg once daily or placebo for 3-6 weeks before ECV and candesartan 16mg once daily or placebo for 6 months after ECV. Serum levels of YKL-40 were measured in fasting blood samples collected at baseline and at end of the study. Mean age was 64±11 years, and 39 (22.8%) were women. Sinus rhythm was maintained for 6 months after ECV in 41 (23.9%). Baseline levels of YKL-40 were significantly correlated to age (Spearmans rho; rs=0.442; p<0.001), CHA2DS2-VASc(1) score (rs=0.256; p<0.001) and left atrial diameter (rs=0.185; p=0.017). By use of Kaplan-Meier quartile analysis of baseline YKL-40 levels, no relation between YKL-40 levels and risk of AF recurrence was found. End of study YKL-40 levels were unchanged from baseline, both in patients with AF recurrence and those maintaining sinus rhythm for 6 months. Treatment with candesartan had no influence on serum YKL-40 levels.