Patients with systolic heart failure are thought to be at increased risk for thromboembolic events. Although these patients may have increased hypercoaguable markers, the incidence of stroke is thought to be relatively low. Still, oral anticoagulation with warfarin is sometimes prescribed in these patients to prevent potential thromboembolic events. Current guidelines do not recommend warfarin use in patients with systolic heart failure unless indicated for other cardiovascular conditions. Several studies that have attempted to address this controversy have, as a whole, demonstrated that the rates of thromboembolic events in patients with systolic heart failure taking warfarin are similar to those in patients taking placebo, basically showing no additional protective benefit of warfarin. In addition, these studies have shown an increased risk of bleeding with warfarin. However, these trials are of poor quality to date. The 4 post hoc analyses in this article had warfarin added at the investigators' discretion and included patients with indications for warfarin, such as atrial fibrillation. The 3 randomized trials in this article did not attain enrollment numbers to reach any calculated power and were stopped early; thus, they were unable to detect a difference. Since warfarin has shown benefit in patients with atrial fibrillation and in mechanical heart valves to decrease the risk of thromboembolism, it might stand to reason that warfarin would have the same benefit in systolic heart failure patients without the above indications. However, given the current available data, warfarin is not supported in patients with systolic heart failure in the absence of an indication for this drug.