Atrial fibrillation is the most commonly experienced arrhythmia increasing in prevalence with age. It is estimated that 3 in 1000 under the age of 65 years have atrial fibrillation rising to 9% of people reaching the age of 80 years. The rate of stroke in untreated atrial fibrillation ranges from 5% per year with minimally associated risk factors up to 15-20% per year with associated risk factors such as hypertension, diabetes mellitus, heart failure and a history of vascular disease. The mortality of atrial fibrillation related to stroke is high and estimated at 25% in 12 months.