Quality of stroke prevention care in atrial fibrillation: many moving targets.

In atrial fibrillation (AF), the loss of coordinated electromechanical atrial activity predisposes to impaired atrial emptying, stasis of blood, and a prothrombotic state.1 These factors cause blood clots to form in the heart and embolize systemically to cause stroke or other organ failure.2,3 AF is responsible for 15% of 700 000 strokes in the United States each year, with an estimated annual direct and indirect cost of $57.9 billion in the United States alone.4