A Phase 3, Randomized, Double-Blind, Placebo-Controlled Trial of Flecainide Acetate Inhalation Solution for Cardioversion of Recent-Onset, Symptomatic Atrial Fibrillation to Sinus Rhythm


The study is designed to evaluate the efficacy and safety of FlecIH-103 (flecainide acetate inhalation solution) compared with placebo in patients with recent-onset, symptomatic newly diagnosed or paroxysmal AF.

Study Arms

  • Active Comparator: FlecIH-103 (flecainide acetate inhalation solution)
  • Placebo Comparator: Vehicle-matched inhalation solution (placebo)


  • ≥18 and ≤85 years of age
  • Recent onset of symptomatic newly diagnosed or paroxysmal AF
    • Recent onset is defined as a symptom duration ≥1 and ≤48 hours at time of dosing
    • Newly diagnosed AF is AF that has not been diagnosed previously, independent of its duration
    • Paroxysmal AF is defined as recurrent AF in a patient whose previous AF episode(s) self-terminated (ie, without treatment) or terminated with intervention ≤7 days of onset.
    • A symptomatic recent-onset AF episode post cardiac ablation for paroxysmal AF would be considered eligible