Atrial fibrillation (AF) is recognized as a common cardiac arrhythmia associated with significant morbidity and mortality. The mechanism of AF depends on the type, paroxysmal (P) AF is usually secondary to autonomic imbalance and chronic (C) AF is typically secondary to cardiovascular dysfunction. There is significant overlap as most patients with PAF will eventually develop CAF. Therapeutic considerations depend mostly on the clinical situation ranging from emergent electrical therapy for unstable patients to no therapy for asymptomatic patients. Most patients are mildly symptomatic from rapid heart rate (ventricular response) and benefit from drugs designed to create AV block. Anticoagulation is important additional therapy in order to prevent thromboemboli. Reversion of AF and maintenance of sinus rhythm would be the ideal goals of therapy except for the toxicity of available agents. As a result many patients would be best left in AF as the rhythm of choice.