--- - |2 Abstract The natural polyphenol resveratrol and its analogue piceatannol have various beneficial effects including antiarrhythmic properties. The aim of the present study was to examine potential electrophysiologic effects in an experimental whole‐heart model of atrial fibrillation (AF). Simultaneous infusion of resveratrol (50μM) or piceatannol (10μM) in rabbit hearts resulted in an increase of atrial refractory period. Both agents induced a significant slowing of atrial conduction and of intrinsic heart rate. In both groups, a trend towards a reduction of AF and a regularization of AF was observed. This article is protected by copyright. All rights reserved. - Clinical and Experimental Pharmacology and Physiology, Volume 0, Issue ja, -Not available-.