Serum levels of nicotinamide-adenine dinucleotide phosphate oxidase 4 are associated with non-valvular atrial fibrillation

Recent evidence indicates that nicotinamide-adenine dinucleotide phosphate oxidase (NOX)-derived reactive oxygen species have a pivotal role in the development of atrial fibrillation (AF). The present study aimed to investigate the potential association between serum levels of NOX4, as well as inflammatory biomarkers and AF. In total, 108 patients with AF (71 with paroxysmal AF and 37 with persistent/permanent AF) and 68 patients without AF, as the controls, were enrolled. The demographic, clinical, laboratory, electrocardiographic and echocardiographic characteristics were carefully recorded. Serum levels of myeloperoxidase (MPO), high-sensitivity C-reactive protein (hs-CRP) and NOX4 were assessed. Left atrial diameter (LAD), left ventricular end-diastolic diameter and P-wave dispersion were significantly increased in patients with paroxysmal AF and persistent/permanent AF compared with the controls, while NOX4 levels were significantly higher in patients with paroxysmal AF and persistent/permanent AF compared to the controls (155.57±90 and 155.88±64.79 vs. 126.72±23.51 pg/ml, respectively, P<0.05). A significant correlation between serum NOX4 levels and hs-CRP, and between NOX4 levels and MPO was also evident (r=0.170; r=0.227, P<0.05, respectively). Multivariate analysis demonstrated that the baseline serum NOX4 level was independently associated with paroxysmal AF [odds ratio (OR)=1.014; 95% confidence interval (CI), 1.001-1.027; P<0.05] and with persistent/permanent AF (OR=1.022; 95% CI, 1.000-1.044; P<0.05). There appears to be an association between increased NOX4 levels and AF, suggesting NOX4 involvement in the pathophysiology of human AF. Further studies are required to elucidate its role in atrial remodeling and to examine its potential prognostic impact.