From a clinical point of view, pharmacological or electrical cardioversion of recent-onset AF is a desirable approach which, however, is potentially complicated by an increased risk of thromboembolic events, especially when there is uncertainty as to the time of onset of the arrhythmia. We have proposed that the observed short-term kinetics of serum NTproBNP levels could be used to assess the recency of onset of AF in patients who are potential candidates for cardioversion.