Dr Howard: contributed as a panelist. Dr Lane: contributed as a panelist. Dr Eckman: contributed as a resource consultant. Dr Fang: contributed as a panelist. Dr Hylek: contributed as a panelist. Dr Schulman: contributed as a panelist. Dr Go: contributed as a panelist. Dr Hughes: contributed as a panelist. Dr Spencer: contributed as a panelist. Dr Manning: contributed as a panelist. Dr Halperin: contributed as a panelist. Dr Lip: contributed as Deputy Editor and senior author. Financial/non nancial disclosures: The authors of this guide- line provided detailed con ict of interest information related to each individual recommendation made in this article. A grid of these disclosures is available online at http://chestjournal. chestpubs.org/content/141/2_suppl/e531S/suppl/DC1. In summary, the authors have reported to CHEST the following con icts of interest: Over the past 3 years, Dr Singer has received grant support from the Eliot B. and Edith C. Shoolman fund of Massachusetts General Hospital (MGH) to study stroke in atrial brillation. He has also received research grant support (through MGH) from Daiichi-Sankyo, Inc, to study hemorrhage risk in patients with atrial brillation taking warfarin. Dr Singer has been supported by the National Institutes of Health (National Heart, Lung, and Blood Institute and National Institute on Aging) grant funding to study stroke risk in patients with atrial brillation. He has served as a con- sultant on stroke prevention in atrial brillation to Bayer Healthcare Pharmaceuticals; Boehringer Ingelheim GmbH; Bristol-Myers Squibb; Daiichi-Sankyo, Inc; Johnson & Johnson; Merck and Co, Inc; P zerInc; and Sano -Aventis LLC. Dr. Singer has published numer- ous articles on stroke prevention in atrial brillation and has given numerous lectures and research presentations on this topic. 