Antazoline in Rapid Cardioversion of Paroxysmal Atrial Fibrillation

Inclusion Criteria: * Written informed consent for participating in the study and written standard version of informed consent for cardioversion accepted in Institute of Cardiology, Warsaw, Poland * Age above 18 and good general condition * Potassium level over 3.5 mmol/l * Stable cardio-pulmonary state on enrollment * In case of unclear history of heart failure or suspicion of impaired left ventricle function echocardiography is indicated prior to enrollment * A long-term antiarrhythmic drug therapy is allowed Exclusion Criteria: * Lack of written informed consent * Antazoline allergy * AF related to significant valvular disease * Clinically significant heart failure or ejection fraction \< 55% * Diastolic blood pressure (BP) \< 100mmHg * History of significant bradyarrhythmia not treated with permanent pacemaker * QT prolongation over 440ms or QTc (Bazett's formula) over population norm * Tachycardia \> 160' * Advanced liver or kidney failure * Acute coronary syndrome, coronary artery by-pass graft, stroke or transient ischemic attack within 30 days before enrollment * Preexcitation in ECG not treated by radiofrequency ablation of accessory pathway * Signs and symptoms of ischemia related to AF * An investigational drug used within 30 days before enrollment * Pregnancy or breast feeding