Determinants of brain natriuretic peptide levels in patients with lone atrial fibrillation

Background: Although brain natriuretic peptide (BNP) is increasingly being used for screening and monitoring of congestive heart failure, its utility in patients with lone atrial fibrillation (AF) is unclear. Methods and Results: Plasma BNP levels were measured and comprehensive transthoracic echocardiography was performed in 96 subjects (47: sinus rhythm, 49: AF). Patients with structural heart disease were excluded. Potential determinants of BNP levels were identified by univariate and multivariate analyses. Individuals with AF had higher BNP levels than those with sinus rhythm (150±114 vs 49±61 pg/ml, p<0.001) The left atrial (LA) volume index (r=0.63, p<0.001), the pulmonary artery systolic pressure (r=0.45, p=0.006), and the early mitral inflow velocity (E)/mitral annular velocity (E') (r=0.36, p=0.04) were found to be independently correlated with BNP level. The correlations between BNP level and LA volume index (p=0.001) or E/E' (p=0.03) were unaltered when subjects with sinus rhythm were removed from the analysis. Conclusions: BNP levels significantly correlated with LA volume index and E/E' in patients with lone AF, which indicates that the BNP level may reflect early left ventricular dysfunction and LA enlargement in this patient population.