F10 and atrial fibrillation: In another study (The Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation [ROCKET AF]) of patients with atrial fibrillation on rivaroxaban or warfarin, 5% of the patients experienced a GI bleed, which affected mostly the upper GI tract [16].