Stroke is the third leading cause of death in the US, primarily afflicting the elderly. Nearly 15% of all strokes are related to atrial fibrillation, a relatively common arrhythmia. Antithrombotic agents (aspirin, warfarin) are used in the prevention of stroke-associated atrial fibrillation; however, they are often underutilized. The expanded use of antithrombotic agents could reduce the number of atrial fibrillation-related strokes by half. The use of warfarin demands an ability to follow instructions closely. A systematic approach to anticoagulation management has been shown to improve clinical outcomes.