LAUSR

Former studies corroborated promising quinidine-like properties of antazoline mesylate facilitating rapid cardioversion atrial fibrillation (AF). Still, paucity of data exists concerning direct comparison of antazoline to other antiarrhythmic agents. The study aimed to verify the hypothesis that intravenous antazoline is non-inferior to amiodarone and/or propafenone in terms of rhythm conversion rate and safety among patients with AF. After reviewing 2344 consecutive medical records with I48 code of international classification of diseases (ICD), 505 eligible patients (21.5%) with paroxysmal or persistent AF who underwent emergent pharmacological cardioversion in the real-world setting of emergency department were enrolled in retrospective observational analysis. The choice of antiarrhythmic drug was left to the discretion of attending physician. Antazoline group was separately matched with corresponding amiodarone (n=218) and propafenone (n=90) cohort using propensity score matching (PSM) with nearest neighbor algorithm (ratio 1:1), adjusting for age, sex, arterial hypertension, diabetes, depressed left ventricular ejection fraction, coronary artery disease, history of stroke, AF ablation, CHA2DS2-VASc score, chronic kidney disease and duration of AF episode. The primary endpoint was restoration of sinus rhythm in the emergency department. The study population (mean age of 67 (59; 74) years; 53.7% females) was characterized by median AF episode duration of 10.5 (5; 24) hours. Antazoline alone was administered in 23.4% of patients (n=118); amiodarone in 47.5% (n=240); propafenone in 9.9% (n=50); while 19.2% (n=97) received ≥2 antiarrhythmic drugs. Before PSM adjustment, antazoline had comparable rhythm conversion rate to propafenone (85.6% vs. 80.0%; P=0.367) and higher than amiodarone treatment (vs. 66.7%, P=0.0002), and greater than combined amiodarone/propafenone group (68.6%; RR 1.25; 95% CI: 1.12–1.39, P=0.0001). After PSM, the use of antazoline was associated with the efficacy similar to propafenone (82.2% vs. 80.0%, RR 1.03; 95% CI: 0.84–1.25, P=0.788) and superior to amiodarone (85.3% vs. 67.0%, RR 1.27, 95% CI: 1.09–1.48, P=0.0019, number needed to treat 5.5; Figure). No major adverse actions were reported in the antazoline group. Antazoline appears to be an efficacious and safe drug for pharmacological cardioversion of AF in real-life setting, which is at least non-inferior to existing antiarrhythmic drugs. None