A Multi-centre Study Comparing the Effects of AZD2927 and Placebo on the Electrical Activity in the Heart in Patients

Inclusion Criteria: * male or postmenopausal female, aged 20 to 80 years inclusive, * clinical indication for catheter ablation of atrial flutter, * history of paroxysmal atrial flutter, with or without paroxysmal AF. Single episodes of persistent atrial flutter or AF requiring cardioversion do not exclude the patient from the study, * sinus rhythm at randomisation, * adequate anticoagulation or antithrombotic treatment according to ESC guidelines 2010 or national guideline, Exclusion Criteria: * cardioversion within 14 days before randomisation, * history of stroke or transient ischaemic attack (TIA). History of significant head trauma, epilepsy or other disorders increasing the risk for seizures, * QTcF \>450 ms or \<350 ms measured in sinus rhythm at randomisation, * history and/or signs of clinically significant sinus node dysfunction. Sinus bradycardia (50 beats per minute or less) at randomisation, * personal or family history of Torsades de Pointes (TdP), any other polymorphic ventricular tachycardia, long QT syndrome, short QT syndrome, Brugada syndrome, or personal history of sustained (\>30 s) monomorphic ventricular tachycardia.