Anticoagulation Issues in Atrial Fibrillation

Despite the compelling evidence that antithrombotic therapy, particularly warfarin, is effective in preventing stroke in patients with nonvalvular atrial fibrillation, these agents remain underused. In addition, despite evidence demonstrating that strokes are prevented when the international normalized ratio is greater than 2 and that hemorrhagic complications are higher when the international normalized ratio is greater than 3 to 3.5, many patients have values that fall outside a therapeutic range. Clinical, transthoracic, and, now, transesophageal information is available to help stratify patients at high risk or low risk for stroke, including those patients undergoing cardioversion.