F10 and atrial fibrillation: In the randomised Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) study, the oral factor Xa inhibitor apixaban at a dose of 5 mg twice daily was more effective than warfarin (target INR, 2.0 to 3.0) in preventing stroke or systemic thromboembolism in patients with AF: hazard ratio, 0.79; 95 % CI, 0.66 to 0.95; P < 0.001 for non-inferiority; P = 0.01 for superiority.