Flecainide to prevent atrial arrhythmia after patent foramen ovale closure, Rationale and design of the randomized AFLOAT study

Introduction Atrial arrhythmia is the most common complication of patent foramen ovale (PFO) closure. The real incidence of post-PFO closure atrial arrhytmia and whether this complication can be prevented is unknown.Methods/Design The Assessment of Flecainide to Lower the PFO closure risk of Atrial fibrillation or Tachycardia (AFLOAT) trial is a prospective, national, multicentre, randomized, open-label, superiority trial with a blind evaluation of all the endpoints (PROBE design). A total of 186 patients are randomized in a 1:1:1 ratio immediately after PFO closure to receive Flecainide (150 mg per day in a single sustained-release (SR) dose) for 6 months (Group 1), Flecainide (150 mg per day in a single SR dose) for 3 months (Group 2), or no additional treatment (standard of care) for 6 months (Group 3). The primary endpoint is the percentage of patients with at least one episode of symptomatic or asymptomatic atrial arrhythmia episode (>= 30 s) recorded within 3 months after PFO closure on long-term monitoring with an insertable cardiac monitor. Whether 3 months of treatment is sufficient compared to 6 months will be analysed as a secondary objective of the study.Conclusion AFLOAT is the first trial to test the hypothesis that a short treatment with oral Flecainide can prevent the new-onset of atrial arrhythmia after PFO closure.Clinical trial registration NCT05213104 (clinicaltrials.gov). Graphical Abstract Design of the AFLOAT trial; AA: atrial arrhythmia; ICM = insertable cardiac monitor; od = once a day; PFO = patent foramen ovale; SR = sustained-release.