Characterization of cardiac brain natriuretic peptide release in patients with paroxysmal atrial fibrillation undergoing left atrial ablation.

BACKGROUND Paroxysmal atrial fibrillation (PAF) is associated with elevated levels of brain natriuretic peptide (BNP). The exact cardiac source and implications of this are currently unknown, as are the effects of left atrial ablation on cardiac BNP release. We sought to investigate BNP levels at different cardiac sites in PAF patients before and after left atrial ablation and compare these with a non-atrial fibrillation control cohort. METHODS AND RESULTS Twenty PAF patients (52+/-10 years, 70% men; left ventricular ejection fraction, 55+/-3%) undergoing ablation were studied, BNP levels were measured at different cardiac sites before and after ablation and compared with a control cohort undergoing ablation for left lateral accessory pathways (10 patients, 41+/-11 years; left ventricular ejection fraction, 55+/-4%). In both cohorts, the coronary sinus BNP levels were the greatest. The PAF cohort had significantly greater BNP levels than the control cohort at all sites before and after ablation. Ablation of the left atrium was associated with a significant decrease in coronary sinus BNP levels (P=0.05) and transcardiac BNP gradient (P=0.03). This was not observed in the control cohort. CONCLUSIONS BNP levels are elevated in PAF, with the highest levels in the coronary sinus. Ablation of the left atrium was associated with an immediate decrease of BNP levels, implicating this as the source.