A Study to Select the Dose and Evaluate the Effectiveness and Safety of the Drug Refralon®, Tablets, 1 mg for Long-term Use to Prevent Recurrence of Atrial Fibrillation/Flutter After Terminating Its Persistent Form

A Multicenter, Randomized, Double-blind, Placebo-controlled, Parallel Group Study to Select the Dose and Evaluate the Effectiveness and Safety of the Drug Refralon®, Tablets, 1 mg (Pharmproekt JSC) for Long-term Use to Prevent Recurrence of Atrial Fibrillation/Flutter After Terminating Its Persistent Form

Refralon® tablets in two different doses (1 or 2 tablets per day) will be evaluated vs. placebo in patients with persistent atrial fibrillation/flutter after synus rhythm restoration in order to prevent recurrence of arrhythmia. Efficacy and safety of Refralon® tablets will be studied, its optimal dose will be selected and its pharmacokinetics will be evaluated in 14 days, 1, 3 and 6 months.

Inclusion Criteria:

• Persistent form of AF/AFL lasting 7 days - 1 year (including patients who have previously undergone ineffective catheter or surgical ablation of AF or AFL and patients with a pacemaker or implanted cardioverter-defibrillator (ICD));
• Basic rhythm - AF and/or AFL according to the results of 12-lead ECG at randomization (Visit 2);
• Left ventricular ejection fraction (LVEF) >40% according to the Simpson method;

Exclusion Criteria:

• Intake of class IA, IC and class III antiarrhythmic drugs less than 7 days (for amiodarone less than 60 days) before the study drug intake;
• History of myocardial infarction or other structural heart disease;
• QT prolongation over 500 ms.