The reinvented old player – an antazoline is effective in pharmacological cardioversion of atrial fibrillation

Abstract Introduction Antazoline (ANT) is an old antihistaminic medication with antiarrhythmic properties. After intravenous administration ANT exerts rapid antiarrhythmic effect often resulting in conversion of atrial fibrillation (AF) to sinus rhythm (SR) and is widely used in Poland for this purpose in the last years. However, published data on its effectiveness, safety and clinical utility for rapid AF termination are limited and ANT is not recognized as a cardioversion drug. Aim To assess the real-world efficacy of ANT for pharmacological cardioversion of paroxysmal and persistent non-valvular AF. Methods Our single center, retrospective, observational study included patients (pts) with history paroxysmal or persistent AF episode lasting less than 6 months, in stable cardiopulmonary condition who were qualified for elective pharmacological cardioversion with intravenous ANT. The primary end-point was the conversion of AF to SR confirmed in electrocardiography (ECG) during the 6-hours observation. Results A total of 176 pts (mean age 68.4±12.0 years, 49% male) were enrolled into the study. In 93 patients (52%) AF duration was shorter than 48 hours and median AF duration time was 24 (7–432) hours. The overall success rate of pharmacological cardioversion of AF with intravenous ANT was 45.5% (80/176 pts). The mean used dose of ANT was 250.9±65.4mg. The subgroup analysis, regarding the AF duration, suggested the effectiveness of ANT mainly in in short-lasting AF (effectiveness of antazoline based cardioversion for AF lasting