This clinical review is intended to assist emergency physicians manage patients who present to the emergency department (ED) with acute/recent-onset atrial fibrillation (AF) or flutter (AFL). This article is based primarily on the 2021 Canadian Association of Emergency Physicians (CAEP) Acute Atrial Fibrillation/Flutter Best Practices Checklist. We encourage readers to download the open access CAEP Checklist article (https://link.springer.com/article/10.1007/s43678-021-00167-y) and the free smartphone app (CAEP Atrial Fibrillation Guide). We focus on four key elements of ED care: assessment and risk stratification, rate and rhythm control, short-term and long-term stroke prevention, and disposition and follow-up. It is important to determine if AF/AFL with rapid ventricular response is a primary arrhythmia or secondary to medical causes. While it is unusual for patients with primary AF to be unstable, urgent cardioversion is occasionally required. The criteria for when cardioversion is safe have recently changed and it is essential that physicians are well versed in them. When rhythm control is not safe, provide effective and safe IV rate control. When rhythm control is safe, either pharmacological or electrical cardioversion acceptable, per patient and physician preference. Rapid ventricular pre-excitation (Wolff-Parkinson-White Syndrome) usually, but not always, requires urgent electrical cardioversion. ED physicians should prescribe oral anticoagulants at discharge if indicated. No specific direct oral anticoagulant is preferred, and references should be freely consulted for optimal dosing. Hospital admission is rarely required for acute AF/AFL patients, who should be given good discharge instructions.
Keywords: Atrial Fibrillation; Atrial Flutter; Cardioversion; Emergency Department.