Electrophysiological Properties of the Atrium After Cardioversion of Chronic Atrial Fibrillation

Relation to the Plasma Brain Natriuretic Peptide Level

Abstract

Background: Brain natriuretic peptide (BNP) level has been shown to increase in patients with chronic atrial fibrillation (CAF) without overt heart failure (HF). Although atrial electrical remodeling associated with CAF has been described, little is known about the effects of the BNP level on the electrophysiological properties in CAF patients.
Methods and results: In 42 CAF patients without overt HF, the atrial monophasic action potential duration (MAPD) at pacing cycle lengths (CLs) of 300-800 msec and P-wave signal-averaged electrograms were recorded after cardioversion. The MAPDs for all CLs were significantly longer in patients with a BNP concentration greater than the 50th percentile (group 1, BNP = 215 ± 118.2 pg/mL) than in patients with a concentration less than the 50th percentile (group 2, BNP = 68.3 ± 20.9 pg/mL), resulting in a similar value in the MAPDs at CLs of 350 and 600 msec for group 1 and the control patients (n = 8). The slope value of the MAPDs between CLs of 350 and 600 msec was normal in group 1, but slightly lower in group 2 than in group 1 and control patients. The filtered P-wave duration did not differ between the two groups.
Conclusions: These electrophysiological characteristics related to the BNP level suggest that the atrial repolarization may be affected by a latent ventricular dysfunction.