Class of Recommendation and Level of Evidence The Class of Recommendation (COR) indicates the strength of recommendation, encompassing the esti- mated magnitude and certainty of benefit in proportion to risk. The Level of Evidence (LOE) rates the quality of scientific evidence supporting the intervention on the basis of the type, quantity, and consistency of data from clinical trials and other sources (Table 1).P-5 Glenn N. Levine, MD, FACC, FAHA Chair, ACC/AHA Task Force on Clinical Practice Guidelines CLINICAL STATEMENTS AND GUIDELINES The purpose of this document is to update the 2014 AHA/ACC/HRS Guideline for the Management of Pa- tients With Atrial Fibrillation S1.3-1 (2014 AF Guideline) in areas for which new evidence has emerged since its publication. The scope of this focused update of the 2014 AF Guideline includes revisions to the section on anticoagulation (because of the approval of new med- ications and thromboembolism protection devices), revisions to the section on catheter ablation of atrial fibrillation (AF), revisions to the section on the man- agement of AF complicating acute coronary syndrome (ACS), and new sections on device detection of AF and weight loss. The areas of the 2014 AF Guideline that were updated were limited to those for which impor- tant new data from clinical trials had emerged and/ or new US Food and Drug Administration (FDA) indi- cations for thromboembolism protection devices have appeared in the data available to the writing group up to August 2018. All recommendations (new, modified, and un- changed) for each updated clinical section are included to provide a comprehensive assessment. The text ex- Table 1. 