Flecainide Versus Amiodarone in the Cardioversion of Paroxysmal Atrial Fibrillation at the Emergency Department, in Patients With Coronary Artery Disease Without Residual Ischemia

Inclusion Criteria: 1. Age: 18-85 years old 2. Paroxysmal Atrial Fibrillation, documented by 12-lead ECG, with one of the following: 1. Atrial Fibrillation onset less than 48 hours from the time of presentation to the Emergency Department 2. Atrial Fibrillation onset between 48 hours and 7 days from the time of presentation to the Emergency Department, and patient has been on anticoagulation for at least 30 days 3. History of Coronary Artery Disease without residual ischemia, defined by one of the following criteria: * PCI \<= 1 year, or * CABG \<= 3 years, or * Negative imaging-based stress testing within 1 year, and: * History of known coronary artery stenosis \> 60% without revascularization, or * PCI \>= 1 year, or * CABG \>= 3 years 3. Ejection Fraction \> 35% (documented by cardiac ultrasound at the Emergency Department, or within 1 year) 4. Signed informed consent from the patient or legal representative. Exclusion Criteria: 1. Based on ECG at the Emergency Department: 1. Atrial Flutter 2. Newly documented Left Bundle Branch Block (LBBB) 3. Newly documented Right Bundle Branch Block (RBBB) with QRS duration \> 150ms 2. Previously documented 24-hour ECG holter monitoring with \> 720 poly PVCs/24hours, or non sustained ventricular tachycardia 3. No history of coronary artery disease 4. ST-Segment Elevation Myocardial Infarction (STEMI) 5. Non-ST-Segment Elevation Myocardial Infarction (NSTEMI), according to ESC 2020 guidelines on NSTEMI: 1. If troponin at t0h is over the "low" criterion on table of the cutoff values 2. If the change of troponin (Δtroponin) at t1h is over the respective cutoff value at the table for the cutoff values 6. Unstable angina, defined as myocardial ischemia at rest or at minimum effort, in the absence of acute injury/necrosis of myocardial cells 7. Known residual ischemia: 1. Positive imaging-based stress testing 2. Negative imaging-based stress testing \>= 1 year, and: * History of known coronary artery stenosis \> 60% without revascularization, or * PCI \>= 1 year, or * CABG \>= 3 years 8. History of acute coronary syndrome within 1 year 9. Severe Aortic Valve Stenosis (mean pressure gradient \> 40mmHg, AVA \< 1cm/m\^2) 10. Severe Chronic Kidney Disease (stage \>= 4) 11. Severe systematic disease, including neoplasmatic disease under any antineoplasmatic treatment, liver failure, infection with fever 12. Use of strategy "pill in the pocket", by taking flecainide (max 200mg) or propafenone (max 600mg) within 6 hours prior to Emergency Department visit 13. Known dysanexia or allergy to flecainide or amiodarone 14. Pregnancy or/and breastfeeding 15. Participation in any other clinical trial 16. Life expectancy less than 1 year 17. Inappropriate, unfit, or unwilling to follow the desingated protocol procedures.