How early is early enough to prevent stroke in atrial fibrillation?

Atrial fibrillation (AF) is a potent risk factor for stroke, being responsible for 20% of ischemic strokes. Subclinical AF burden has received much attention, especially in the context of patients with cryptogenic strokes. However, little is known about the impact of subclinical episodes of rapid atrial rate and the primary risk of stroke and systemic embolism. Healey et al. investigated whether subclinical rapid atrial rate detected by implanted devices was associated with the risk of ischemic stroke in patients without clinical evidence of AF. The current article discusses the potential implications of the above results.