The prevalence of atrial fibrillation is 11% in persons older than 70 years and rises to 17% in those aged 84 years or more. One-year mortality ranges from 0.2 to 16%, being highest in elderly patients, and is associated with a 4.8-fold increased risk of stroke. Atrial fibrillation can be cardioverted to normal sinus rhythm electrically or pharmacologically and rapid ventricular rate can be controlled with drugs. While anti-coagulation prevents embolic events in those with atrial fibrillation, the decision to anticoagulate should be based on an assessment of the risk/benefit ratio.