Atrial Fibrillation (AF) is the most common disorder of the rhythm disturbance, especially in older adults. The incidence and prevalence of AF increases significantly with age: less than one new case per 1000/year before age 40 to 20/1000 per year after the age of eighty. AF represents 1% of emergency department (ED) visits a third of which are inaugural or recurrent. The causes are varied from cardiac (ischemic cardiac disease, valvular, high blood pressure, heart failure, pericarditis, myocarditis) to extra cardiac etiologies (pulmonary embolism, thyroid disorders, thyrotoxicosis, alcohol, shock, chest trauma, electrolyte disorders, dehydration). While the diagnosis is given quickly by reading the electrocardiogram (ECG), its management both in terms of therapeutic strategy that of choice of care pathway is complex as evidenced by the diversity of possibilities and the difference in practice. Specific recommendations have been published by the French Society of Emergency Medicine in 2015. Our study aims to investigate guidelines implementation in French ED, especially the contribution of diagnostic tests and initiated treatments. Therapeutic strategies are evaluated with a follow up at 3 months, 6 months and 1 year, reporting cardiovascular events and long-term treatment.

This study is non-interventional, recruiting patients presenting to ED with AF. No other epidemiological studies on the subject are available to calculate the required number of subjects and analyze the power of the study. Investigators planned to include 1 575 patients (45 patients in 35 centres) with a minimum targeted 1000 patients to be included in the 30-40 participating centers. The study aims to assess patients characteristics (age, sex, body mass index, type of AF, Congestive Heart failure Hypertension Age Diabetes Stroke - VAscular disease (CHA2DS2- VAsc) Score, Hypertension Abnormal liver/renal function, Stroke history, Bleeding history or predisposition, Labile INR, Elderly, Drug/alcohol usage (HAS-BLED) score), methods of diagnostic (blood tests, ECG, Imaging tests, Cardiac echography), treatment pattern (drugs administered in ED, drug prescribed at hospitalization discharge), patient pathway (orientation after ED admission, discharge, consultation planned), drug-related observance reported by the patient.

Data are collected in a case report form (CRF). Source data verification is performed by sites investigators. A data dictionary containing detailed descriptions of each variable is shared with investigators. Sites monitoring is planned by a clinical research assistant for completing missing data.

Statistical analysis: Data are medians and interquartile ranges (IQRs) for continuous variables, and numbers and percentages for qualitative variables. Stratified analysis of subgroups (age, sex, anticoagulant treatment, examination performed …) will be considered.

Inclusion Criteria:

• Atrial fibrillation diagnosis on ECG

Exclusion Criteria:

• Refusal of the patient to participate

All patients over 18 years admitted to the emergency department with an AF diagnosis on ECG