Rapid pharmacological cardioversion of recent-onset atrial fibrillation using antazoline in elderly patients

INTRODUCTION There is insufficient evidence on the efficacy and safety of pharmacological cardioversion of recent-onset atrial fibrillation (AF) in elderly patients. Antazoline has been shown to be effective and safe in various patient populations. OBJECTIVES We aimed to compare the clinical efficacy and safety of intravenous antazoline for pharmacological cardioversion of recent-onset AF between patients aged 75 years or older and those younger than 75 years. PATIENTS AND METHODS This retrospective analysis was conducted using data derived from emergency room medical records of patients referred for pharmacological cardioversion due to symptomatic AF lasting less than 48 hours. The threshold for old age was set at 75 years. Conversion to sinus rhythm was considered the primary efficacy outcome. The primary safety outcome was defined as any adverse event requiring hospitalization. RESULTS The study included 334 participants, of whom 110 patients were aged 75 years or older (study group) and 224 patients were younger than 75 years (controls). Successful cardioversion was achieved using lower mean (SD) antazoline doses in the study group than in controls: 151 (59) mg vs 168 (58) mg (P = 0.039). Study and control groups showed a similar efficacy and safety of antazoline (78.2% and 68.3%, respectively; odds ratio [OR], 1.66; 95% CI, 0.98-1.31; P = 0.06) as well as hospitalization rates (0.9% and 4.0%, respectively; OR, 0.22; 95% CI, 0.03-1.75; P = 0.17). CONCLUSIONS Intravenous antazoline seems to be effective and safe for pharmacological cardioversion of recent-onset AF in elderly patients in the emergency setting.