Stroke prevention in atrial fibrillation: Commentary regarding the AAN's evidence-based guideline update.

Atrial fibrillation is a common, potentially preventable cause of disabling stroke in the elderly, particularly in elderly women, resulting from embolism of stasis-precipitated thrombi formed in the left atrial appendage. In 1989, the first randomized clinical trial of anticoagulant therapy in atrial fibrillation showed that warfarin produced a large reduction in ischemic stroke.1 In the ensuing 25 years, more than 40 additional randomized trials have permitted stroke prophylaxis to be importantly refined. It has been a period of remarkable progress in stroke prevention. Here, we discuss selected aspects of the American Academy of Neurology (AAN)'s evidence-based guideline update.2.