Cinderella drug: an antazoline is effective in pharmacological cardioversion of atrial fibrillation - Single center experience

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Antazoline (ANT) is an old antihistaminic medication with antiarrhythmic properties. After intravenous administration ANT exerts rapid antiarrhythmic effect often resulting in conversion of persistent atrial fibrillation (AF) to sinus rhythm (SR). 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 We conducted a single center, retrospective, observational study including 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 <48h vs others: 75.3% vs 12.0%, p < 0.001). In multivariable logistic regression model AF duration (for every 24h in AF - OR = 0.97; 95% CI 0.96 – 0.98), the left atrium antero-posterior diameter (OR = 0.92; 95% CI 0.86 – 0.99) and the serum creatinine level (OR = 0.15; 95% CI 0.03 – 0.73) were identified as independent predictors of antazoline based pharmacological cardioversion effectiveness, even after adjustment for comorbidities. The ROC curves revealed that the optimal cut-off value for AF duration time predicting ANT’s effectiveness was 48h (AUC = 0.876; 95% CI 0.815 – 0.922). There were only one episode of bradycardia <45 bpm related to ANT administration. Conclusions Intravenous antazoline administration is effective and safe in rapid pharmacological cardioversion of paroxysmal AF, especially in the short-lasting AF (<48 hours) and in patients without the left atrium enlargement and significant renal disease. Abstract Figure.