Classification of atrial fibrillation as a model of decisional analysis for the treatment of patients with current atrial fibrillation observed in the emergency department.

: Atrial fibrillation (AF) is the most common cardiac arrhythmia observed in the emergency room (ER). We propose a new classification of AF which is useful for the standardization of terms to be used for future clinical trials and for clinical management of this arrhythmia in the ER. We recognized three categories: (1) atrial fibrillation lasting less than 72 hours (AF < 72 h); (2) persistent atrial fibrillation and (3) permanent atrial fibrillation. Atrial fibrillation lasting less than 72 hours can be reconverted to sinus rhythm spontaneously or with pharmacological or electrical cardioversion. If AF < 72 h is not treated and the arrhythmia persists for more than 72 hours we recognize persistent AF. In persistent AF the systemic thrombo-embolism is a significant risk and therapeutic anticoagulation must be associated to pharmacological or electrical cardioversion even though transoesophageal echocardiography does not visualize thrombi or spontaneous echocontrast in the cardiac chambers. These treatments can reconvert the persistent AF to sinus rhythm, but, in the absence of treatment, or if treatment fails, the arrhythmia goes into the permanent category. In permanent AF ventricular rate control and anticoagulation, if suitable, are the first choice for stroke prevention.