 Evidence from large clinical studies has shown that patients with heart failure fare better if sinus rhythm can be restored, but on the contrary a rhythm control strategy as intention to treat of cardioversion or antiarrhythmic drugs to achieve sinus rhythm has not been shown to be superior to the strategy of rate control. These apparently contradictory findings might be explained by the poor efficacy and side effects associated with current rhythm control strategies, or could reflect that AF is merely a passive marker of underlying disease severity. However, many studies would point to the former, and it might be hypothesised that the theoretical benefits of sinus rhythm could be seen for real in clinical practice if a superior rhythm-control strategy was used. 