Beta Blockers Plus Intravenous Flecainide for Paroxysmal Atrial Fibrillation: a Real-world Chios Registry (BETAFLEC-CHIOS)

Patient population BETAFLEC-CHIOS, is a single-center registry that was initiated in the "Skylitseion" General Hospital of Chios in January 2020 and is ongoing. Patients are included in the registry if presenting with recent-onset atrial fibrillation (AF) (≤48 hours of onset) and lasting ≥30min, documented by a 12-lead ECG and having received intravenous (IV) flecainide on treating physician's discretion. Exclusion criteria are severe structural or ischemic heart disease (previous cardiac surgery, any cardiomyopathy, myocardial infarction at any time), atrial flutter, sick sinus syndrome, high degree atrioventricular block, bifascicular block, abnormal electrolyte levels (especially hypo- or hyperkalemia) or known sensitivity to flecainide. Continuous monitoring is applied during and after administration of IV flecainide. If no conversion to sinus rhythm is achieved at 2 hours after flecainide infusion initiation, the patient is recorded as "unsuccessful conversion attempt" and forwarded for direct current cardioversion (DCC). All patients were anticoagulated according to the current European Society Guidelines (ESC) or the management of AF \[ESC Afib 2020\].

Flecainide administration Flecainide is given as an IV infusion of 1.5 mg/kg (max 150 mg) in DW 5% over 10 min under continuous monitoring. Concomitant administration of a b-blocker is also applied in all patients. The dose and type of b-blocker are selected according to heart rate during the AF and patient's medical history. "Time to conversion" is calculated as the time interval from the end of the infusion up to when sinus rhythm is observed on the monitor and confirmed subsequently with a 12-lead ECG.

• Flecainide Injectable Product (Drug), also known as Sotalol, Bisoprolol, Metoprolol, Betaxolol: Flecainide is given as an IV infusion of 1.5 mg/kg (max 150 mg) in DW 5% over 10 min under continuous monitoring. Concomitant administration of a b-blocker is also applied in all patients. The dose and type of b-blocker are selected according to heart rate during the AF and patient's medical history.

Primary outcomes

• Number of patients converted to sinus rhythm at 1 hour [1 hour]: Successful cardioversion from atrial fibrillation to sinus rhythm at 1 hour

Secondary outcomes

• Number of patients converted to sinus rhythm at 2 hour [2 hours]: Successful cardioversion from atrial fibrillation to sinus rhythm at 2 hours
• Number of patients with any documented proarrhythmic event [2 hours]: Ventricular tachycardia, ventricular fibrillation, torsades de pointes, atrial flutter with 1:1 atrioventricular conduction
• Number of arrhythmic events managed with defibrillation [2 hours]: Any arrhythmic event managed with defibrillation
• Number of patients with documented severe hypotension [2 hours]: Systolic blood pressure <90 mmHg for >10 min or requiring inotropic support
• Number of patients that discontinued IV flecainide infusion [2 hours]: Discontinuation of the IV flecainide infusion for any reason
• Hospitalization duration [48 hours]: Total length of hospitalization duration in hours

Sex: All, ages: 18 Years to any

Inclusion Criteria:

1. Informed written consent.
2. Recent-onset atrial fibrillation (AF) (≤48 hours of onset) and lasting ≥30min, documented by a 12-lead ECG
3. Administration of intravenous flecainide
4. Administration of an oral b-blocker

Exclusion Criteria:

1. Age <18 years
2. Severe structural or ischemic heart disease (previous cardiac surgery, any cardiomyopathy, myocardial infarction at any time)
3. Atrial flutter, sick sinus syndrome, high degree atrioventricular block, bifascicular block
4. Abnormal electrolyte levels (especially hypo- or hyperkalemia)
5. Known sensitivity to flecainide

• Athanasios Kartalis, Principal investigator, Skylitseio General Hospital of Chios
• Matthaios Didagelos, Principal investigator, AHEPA University General Hospital