 - Background: Different research strategies aim at understanding the mechanisms underlying the maintenance of atrial fibrillation AF, while preventing ventricular pro-arrhythmia related to the use of anti-arrhythmic drugs to restore sinus rhythm. Such aims might be achieved by drugs that effectively terminate reentrant sources identified during AF, along with an atrial specific and atria-preferential blockade of ionic currents. The latter may be especially relevant in paroxysmal AF episodes with fast atrial activation rates, in which INa and IK,ACh are involved in the maintenance of fast atrial reentrant sources underlying AF. 