Correlation between atrial fibrillation, serum amyloid protein A and other inflammatory cytokines

Atrial fibrillation (AF) may occur and persist due to atrial remodeling exacerbated by inflammation. However, whether inflammatory cytokines, such as serum amyloid protein A (SAA), are elevated in patients with atrial arrhythmias remains unclear. In a case-control study design, serum levels of inflammatory cytokines SAA, IL-1, IL-6, TNF-α and high-sensitivity C-reactive protein (hsCRP) were compared between 122 patients with AF and 63 non-AF controls. Of 122 AF patients, 48 had lone AF and 74 organic AF; 65 had paroxysmal AF, 36 persistent AF and 21 permanent AF. In unadjusted analyses, the levels of SAA, hsCRP, TNF-αP, IL-1 and IL-6 were significantly higher in AF patients compared to control patients (P<0.01). Patients with permanent and persistent AF had higher serum levels of inflammatory cytokines than those with paroxysmal AF; all AF patients had higher serum levels than controls (P<0.05). Using a multivariate logistic regression analysis, we found that SAA (OR 3.11; 95% CI, 1.12-6.05), hsCRP (OR 2.53; 95% CI, 1.17-4.38), TNF-α (OR 1.80; 95% CI, 1.03-3.20) and IL-6 (OR 1.21; 95% CI, 0.68-2.87) were correlated with AF (P<0.05). SAA and related inflammatory cytokines are elevated in AF patients. This study is the first to document elevated SAA in AF patients. Although the cause of elevated SAA levels in AF patients remains unknown, elevated SAA may reflect an inflammatory state that promotes the occurrence and persistence of AF.