Acute Atrial Fibrillation and Flutter Treated Electively (AFFELECT) – Rationale and design of the randomized controlled AFFELECT trial

Abstract Background Cardioversion (CV) is commonly used in the emergency department (ED) to treat recent-onset atrial fibrillation (AF) or flutter (AFL). Design The AFFELECT trial (NCT04267159) is an investigator-initiated, prospective, unblinded randomized controlled non-inferiority trial comparing experimental delayed rhythm control (elective CV performed within 5-9 days after the index visit) to standard acute rhythm control (CV performed in ED) in patients with recent-onset (duration 48 hours) symptomatic AF/AFL suitable for rhythm control. A total of 500 patients are randomized in a 2:3 ratio to the acute and delayed groups, respectively, accounting for a possible one-third unplanned early CV rate in the delayed group due to higher symptom burden. Unplanned early CV means that patients with unbearable symptoms are offered the option for an earlier cardioversion (before the 5-9 days target timeline) if needed. Patients randomized to delayed group are discharged immediately after adequate heart rate control (heart rate 110bpm) and anticoagulation and are scheduled an appointment for delayed CV at a cardiology outpatient clinic (in transesophageal echocardiography guidance if required). Patients randomized to acute CV undergo cardioversion in the ED within 48 hours of arrhythmia onset and are assigned to a cardiologic outpatient clinic visit also within 5-9 days. The primary endpoint is the presence of sinus rhythm on electrocardiogram at 4 weeks after the outpatient clinic visit. Conclusion The AFFELECT trial tests whether delayed management of recent-onset AF/AFL is non-inferior alternative to acute CV, aiming to reduce ED burden, number of needed CVs and redirect care to specialized arrhythmia units.