Atrial Fibrillation management is still a matter for debate. Past research has largely been based on the outpatient setting in which patients are followed during ambulatory visits. Very little data exist on the optimal management of AF in the Emergency Department (ED). This study investigated which factors drive different AF treatments in the ED, describing their use in different hospitals. Finally, the efficacy of different strategies in terms of cardioversion in the ED was analyzed. Charts of patients treated for atrial fibrillation (AF) were collected in 6 EDs in a large metropolitan area over a 24-consecutive month period and were reviewed and analysed. Demographics, comorbidities, treatment strategy and ED outcome were collected. Inclusion criteria were symptom onset <3 weeks and stable hemodynamic conditions at presentation. A propensity score was used to adjust for baseline clinical characteristics and to compare the efficacy of different treatments. 3,085 patients were included in the analysis. Variables associated with a rhythm control strategy were onset of symptoms <48 h, age, dyspnea, palpitations, renal failure and the presence of a mechanical valve. Different EDs applied different strategies in terms of drugs used and the electrocardioversion rate, showing heterogeneity in AF management. Adjusting for the propensity score, electrocardioversion and antidysrhythmic drugs of class Ic were more effective than a wait-and-watch strategy in the ED. Despite international guidelines being respected, AF management is heterogeneous in different ED settings. A rhythm control strategy with electrocardioversion and Class Ic drugs is more effective than a wait-and watch approach during the ED visit. Further research, toward an evidence-based approach to the emergent management of AF in the ED, is still needed.