Stroke is a significant cause of mortality and disabling morbidity. The major subtypes of stroke are divided into thrombo-embolic, haemorrhagic and cryptogenic, with each having different predisposing risk factors and management strategies. Atrial fibrillation (AF) is the commonest arrhythmia predisposing to thrombo-embolic stroke. The incidence of AF increases with age, affecting up to 5% in the elderly population. Electrophysiology studies have implicated that spontaneous atrial ectopic beats that originate in or near pulmonary veins adjacent to the left atrium, may initiate paroxysms of AF