Background and objective: Plasma B-type natriuretic peptide (BNP) levels are determined by several factors. The presence of atrial fibrillation (AF) is one of these factors. Meanwhile, plasma BNP levels are well correlated with left ventricular (LV) filling pressure in patients with sinus rhythm. Furthermore, LV filling pressure can be estimated by the ratio of early diastolic transmitral velocity to early diastolic mitral annular velocity (E/e' ratio) in patients with sinus rhythm or with AF. However, it is still unclear if elevated plasma BNP levels reflect increases in LV filling pressure in patients with AF, especially with preserved LV systolic function. This study was designed to examine which factors determine plasma BNP levels in patients with persistent nonvalvular AF and preserved LV systolic function.
Methods and results: We examined 195 clinically stable outpatients with persistent nonvalvular AF and preserved LV systolic function. They underwent comprehensive 2-dimensional and Doppler echocardiography, plasma BNP and creatinine levels, clinical history, and heart rate were determined. Then we statistically analyzed the correlation between plasma BNP levels and several variables including E/e' ratio. On univariate analyses, plasma BNP levels were significantly correlated with age, LV diastolic diameter (LVDd), E/e' ratio, and mitral E wave deceleration time. In addition, plasma BNP levels were significantly higher in males and in patients with a history of congestive heart failure and those who had been administered a ß-blocker. On multiple linear regression analyses, E/e' ratio, age, LVDd, and administration of ß-blocker were independent determinant factors of plasma BNP levels.
Conclusions: Plasma BNP levels in patients with persistent AF and preserved LV systolic function are affected by E/e' ratio, age, LVDd, and administration of ß-blockers.