Assessment of Factors Influencing Plasma BNP Level in Patients with Chronic Atrial Fibrillation and Preserved Left Ventricular Systolic Function

Background and Objectives:Several studies have reported that Brain Natriuretic Peptide (BNP) were increased in patients with chronic atrial fibrillation (AF). The objective of this study was to assess the factors influencing plasma BNP levels in patients with chronic AF and preserved left ventricular (LV) systolic function. Subjects and Methods:Transthoracic echocardiography was performed in 55 patients (25 men, 30 women; mean age 66.6± 11.5 years) with chronic AF. At the same time, plasma BNP was measured with a Triage ® kit (Biosite, San Diego, California). Results:Women, long duration of AF and hypertension were more prevalent in the highest quartile group of BNP levels than in the lowest quartile group of BNP levels. Significant correlations were observed bet- ween plasma BNP levels and the following: mitral E velocity (r=0.339), mitral annular E'-velocity (r=-0.396), ratio of mitral E-velocity and mitral annular E' velocity (r=0.473), left atrium (LA) size (r=0.648), LA volume index (r=0.744), right atrium (RA) volume index (r=0.554), maximal velocity (Vmax) of mitral regurgitation (MR) (r=0.444), tricuspid regurgitation (TR) Vmax (r=0.544), MR grade (r=0.431), TR grade (r=0.427) and LV mass index (r=0.570). In stepwise multiple linear regression analysis, LA volume index (β=0.299, p=0.014), LV mass index (β=0.404, p<0.001) and duration of AF (β=0.488, p<0.001) independently predicted plasma BNP levels in this study subjects. The patients with increased LA volume index exhibited longer duration of AF, larger RA volume index and LV mass index, higher MR Vmax, TR Vmax, MR and TR grade and plasma BNP level. Conclusion:LA volume index, LV mass index and duration of AF were independent predictors of plama BNP level in patients with chronic AF and preserved LV systolic function. (Korean Circulation J 2005;35:605-612)