Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Stroke and thromboembolism occur more frequently in patients with AF and cause substantial morbidity and mortality [1–3]. AF-related strokes are associated with worse disability and longer hospital stays, and an increased mortality rate, compared with strokes that are attributable to other causes [4–7]. Hence, prevention of stroke is vital in the management of patients with AF. Current guidelines recommend oral anticoagulation therapy in patients who are identified as being at moderate-to-high risk of stroke [8,9].