Inflammatory markers in paroxysmal atrial fibrillation and the protective role of renin-angiotensin-aldosterone system inhibitors

BACKGROUND Experimental and clinical studies have shown the importance of inflammation in the pathophysiology of atrial fibrillation (AF). The renin-angiotensin-aldosterone system (RAAS) may play an important role in the pathogenesis of AF in correlation with the inflammatory process. RAAS inhibition may have important therapeutic value in limiting AF. The aim of this study was the correlation between inflammatory markers and recurrent episodes of AF in patients with known paroxysmal atrial fibrillation, with and without treatment with RAAS inhibitors. METHODS AND RESULTS We studied 82 patients with paroxysmal AF recorded at "Niculae Stancioiu" Heart Institute Cluj-Napoca, divided into two groups: group A treated with angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB) and group B without this medication. All patients underwent clinical examination, ECG, echocardiography and determination of plasma levels of inflammatory markers represented by high sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL-6). In the group treated with ACE inhibitors/ARBs, AF burden was significantly lower than in patients without treatment. We obtained a strong positive correlation between blood levels of high-sensitivity CRP and those of IL-6 (r=0.64, p<0.001), the number of yearly AF episodes (r=0.570, p<0.001), LA diameter (r=0.5, p<0.001) and LA volume (r=0.5, p<0.001). We found moderate positive correlations between blood levels of IL-6 and LA diameter (r=0.305, p=0.01), LA volume (r=0.314, p=0.01), the number of yearly AF episodes (r=0.489, p<0.001), the total number of AF episodes (r=0.304, p<0.001), BMI (r=0.473, p<0.001), LA area (r=0.458, p<0.001), LA area index (r=0.334, p=0.007) and LA volume index (r=0.304, p=0.01). The number of yearly AF episodes and BMI values influenced IL-6 blood levels (t=3.46, p=0.001, respectively t=2.17, p=0.03). CONCLUSIONS Inflammation is present in patients with AF, with or without treatment with RAAS inhibitors and is correlated with longer duration of AF, left atrial diameter and left atrial volume. ACE inhibitors and ARBs, acting on cardiac substrate and reducing the inflammatory process, may have a therapeutic protective role of decreasing AF burden.