Independent effect of atrial fibrillation on natriuretic peptide release.

BACKGROUND: We investigated whether the increase of plasma natriuretic peptides (NPs) in atrial fibrillation (AF) is independent of the effect of AF on the left atrial (LA) hemodynamics.

METHODS: Hemodynamically stable patients scheduled for AF ablation underwent assessment of B-type natriuretic peptide (BNP) and mid-regional pro-atrial natriuretic peptide (MR-proANP), echocardiography, and direct measurement of left atrial (LA) pressure. Concentrations of the NPs were compared between patients in AF (n = 31) and controls in sinus rhythm (SR; n = 31) who were matched for age, gender, heart rate, left ventricular ejection fraction, LA volume index, and directly measured mean LA pressure. Eighteen patients underwent serial measurement of NPs and LA pressure during native SR and after 20 min of pacing-induced AF.

RESULTS: Compared to the patients in SR, the patients in AF had 2.6 times higher unadjusted BNP [median (inter-quartile range), 101 (63, 129) vs. 38 (26, 79) ng/L] and two times higher unadjusted MR-proANP [183 (140, 230) vs. 91 (67, 135) pmol/L; both p < 0.001]. Concentrations of both NPs correlated with mean LA pressure in the patients in SR (r = 0.75 for BNP and 0.62 for MR-proANP, both p < 0.001) but not in the patients in AF (r = 0.18 and 0.04, respectively, both p > 0.3). Both NPs increased significantly during induced AF [adjusted median (IQR) relative change, BNP: 27 (22; 40)%, MR-proANP: 75 (64; 99)%, both p < 0.001] without a significant change in the LA pressure.

CONCLUSIONS: The increase of NPs in AF was independent of its effect on the LA hemodynamics.