Title: 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation
Abstract: HomeCirculationVol. 130, No. 232014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUB2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial FibrillationA Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society Craig T. January, MD, PhD, FACC, L. Samuel Wann, MD, MACC, FAHA, Joseph S. Alpert, MD, FACC, FAHA, Hugh Calkins, MD, FACC, FAHA, FHRS, Joaquin E. Cigarroa, MD, FACC, Joseph C. ClevelandJr, MD, FACC, Jamie B. Conti, MD, FACC, FHRS, Patrick T. Ellinor, MD, PhD, FAHA, Michael D. Ezekowitz, MB, ChB, FACC, FAHA, Michael E. Field, MD, FACC, FHRS, Katherine T. Murray, MD, FACC, FAHA, FHRS, Ralph L. Sacco, MD, FAHA, William G. Stevenson, MD, FACC, FAHA, FHRS, Patrick J. Tchou, MD, FACC, Cynthia M. Tracy, MD, FACC, FAHA and Clyde W. Yancy, MD, FACC, FAHA Craig T. JanuaryCraig T. January Search for more papers by this author , L. Samuel WannL. Samuel Wann *Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry and other entities may apply; see Appendix 1 for recusal information. Search for more papers by this author , Joseph S. AlpertJoseph S. Alpert Search for more papers by this author , Hugh CalkinsHugh Calkins Search for more papers by this author , Joaquin E. CigarroaJoaquin E. Cigarroa †ACC/AHA Representative. Search for more papers by this author , Joseph C. ClevelandJrJoseph C. ClevelandJr ‖Society of Thoracic Surgeons Representative. Search for more papers by this author , Jamie B. ContiJamie B. Conti Search for more papers by this author , Patrick T. EllinorPatrick T. Ellinor ‡Heart Rhythm Society Representative. Search for more papers by this author , Michael D. EzekowitzMichael D. Ezekowitz Search for more papers by this author , Michael E. FieldMichael E. Field †ACC/AHA Representative. Search for more papers by this author , Katherine T. MurrayKatherine T. Murray †ACC/AHA Representative. Search for more papers by this author , Ralph L. SaccoRalph L. Sacco †ACC/AHA Representative. Search for more papers by this author , William G. StevensonWilliam G. Stevenson Search for more papers by this author , Patrick J. TchouPatrick J. Tchou ‡Heart Rhythm Society Representative. Search for more papers by this author , Cynthia M. TracyCynthia M. Tracy †ACC/AHA Representative. Search for more papers by this author and Clyde W. YancyClyde W. Yancy †ACC/AHA Representative. Search for more papers by this author Originally published28 Mar 2014https://doi.org/10.1161/CIR.0000000000000041Circulation. 2014;130:e199–e267is corrected byCorrectionOther version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 1, 2014: Previous Version 1 Table of ContentsPreamble e201Introduction e2031.1. Methodology and Evidence Review e2031.2. Organization of the Writing Committee e2031.3. Document Review and Approval e2031.4. Scope of the Guideline e203Background and Pathophysiology e2042.1. Definitions and Pathophysiology of AF e2052.1.1. AF Classification e2062.1.1.1. Associated Arrhythmias e2062.1.1.2. Atrial Flutter and Macroreentrant Atrial Tachycardia e2062.2. Mechanisms of AF and Pathophysiology e2072.2.1. Atrial Structural Abnormalities e2072.2.2. Electrophysiological Mechanisms e2082.2.2.1. Triggers of AF e2082.2.2.2. Maintenance of AF e2082.2.2.3. Role of the Autonomic Nervous System e2092.2.3. Pathophysiological Mechanisms e2092.2.3.1. Atrial Tachycardia Remodeling e2092.2.3.2. Inflammation and Oxidative Stress e2092.2.3.3. The Renin-Angiotensin-Aldosterone System e2092.2.3.4. Risk Factors and Associated Heart Disease e209Clinical Evaluation: Recommendation e2103.1. Basic Evaluation of the Patient With AF e2103.1.1. Clinical History and Physical Examination e2103.1.2. Investigations e2103.1.3. Rhythm Monitoring and Stress Testing ………..e210Prevention of Thromboembolism e2114.1. Risk-Based Antithrombotic Therapy: Recommendations e2114.1.1. Selecting an Antithrombotic Regimen—Balancing Risks and Benefits e2124.1.1.1. Risk Stratification Schemes (CHADS2, CHA2DS2-VASc, and HAS-BLED) e2134.2. Antithrombotic Options e2144.2.1. Antiplatelet Agents e2144.2.2. Oral Anticoagulants e2154.2.2.1. Warfarin e2154.2.2.2. New Target-specific Oral Anticoagulants e2164.2.2.3. Considerations in Selecting Anticoagulants e2184.2.2.4. Silent AF and Stroke e2194.3. Interruption and Bridging Anticoagulation e2204.4. Nonpharmacological Stroke Prevention e2214.4.1. Percutaneous Approaches to Occlude the LAA e2214.4.2. Cardiac Surgery—LAA Occlusion/Excision: Recommendation e221Rate Control: Recommendations e2225.1. Specific Pharmacological Agents for Rate Control e2235.1.1. Beta-Adrenergic Receptor Blockers e2235.1.2. Nondihydropyridine Calcium Channel Blockers e2245.1.3. Digoxin e2245.1.4. Other Pharmacological Agents for Rate Control e2245.2. AV Nodal Ablation e2245.3. Selecting and Applying a Rate-Control Strategy e2255.3.1. Broad Considerations in Rate Control e2255.3.2. Individual Patient Considerations e226Rhythm Control e2266.1. Electrical and Pharmacological Cardioversion of AF and Atrial Flutter e2266.1.1. Prevention of Thromboembolism: Recommendations e2266.1.2. Direct-Current Cardioversion: Recommendations e2276.1.3. Pharmacological Cardioversion: Recommendations e2276.2. Pharmacological Agents for Preventing AF and Maintaining Sinus Rhythm e2296.2.1. Antiarrhythmic Drugs to Maintain Sinus Rhythm: Recommendations e2296.2.1.1. Specific Drug Therapy e2326.2.1.2. Outpatient Initiation of Antiarrhythmic Drug Therapy e2336.2.2. Upstream Therapy: Recommendations e2346.3. AF Catheter Ablation to Maintain Sinus Rhythm: Recommendations e2346.3.1. Patient Selection e2356.3.2. Recurrence After Catheter Ablation e2356.3.3. Anticoagulation Therapy Periablation e2366.3.4. Catheter Ablation in HF e2366.3.5. Complications Following AF Catheter Ablation e2366.4. Pacemakers and Implantable Cardioverter-Defibrillators for Prevention of AF e2366.5. Surgical Maze Procedures: Recommendations e236Specific Patient Groups and AF e2397.1. Athletes e2397.2. Elderly e2407.3. Hypertrophic Cardiomyopathy: Recommendations e2407.4. AF Complicating ACS: Recommendations e2407.5. Hyperthyroidism: Recommendations e2417.6. Acute Noncardiac Illness e2417.7. Pulmonary Disease: Recommendations e2427.8. WPW and Pre-Excitation Syndromes: Recommendations e2427.9. Heart Failure: Recommendations e2437.10. Familial (Genetic) AF: Recommendation e2447.11. Postoperative Cardiac and Thoracic Surgery: Recommendations e244Evidence Gaps and Future Research Directions e244References e245Appendix 1. Author Relationships With Industry and Other Entities (Relevant) e258Appendix 2. Reviewer Relationships With Industry and Other Entities (Relevant) e260Appendix 3. Abbreviations e266Appendix 4. Initial Clinical Evaluation in Patients With AF e267PreambleThe medical profession should play a central role in evaluating the evidence related to drugs, devices, and procedures for the detection, management, and prevention of disease. When properly applied, expert analysis of available data on the benefits and risks of these therapies and procedures can improve the quality of care, optimize patient outcomes, and favorably affect costs by focusing resources on the most effective strategies. An organized and directed approach to a thorough review of evidence has resulted in the production of clinical practice guidelines that assist clinicians in selecting the best management strategy for an individual patient. Moreover, clinical practice guidelines can provide a foundation for other applications, such as performance measures, appropriate use criteria, and both quality improvement and clinical decision support tools.The American College of Cardiology (ACC) and the American Heart Association (AHA) have jointly engaged in the production of guidelines in the area of cardiovascular disease since 1980. The ACC/AHA Task Force on Practice Guidelines (Task Force), whose charge is to develop, update, or revise practice guidelines for cardiovascular diseases and procedures, directs this effort. Writing committees are charged with the task of performing an assessment of the evidence and acting as an independent group of authors to develop, update, or revise written recommendations for clinical practice.Experts in the subject under consideration are selected from both organizations to examine subject-specific data and write guidelines. Writing committees are specifically charged to perform a literature review; weigh the strength of evidence for or against particular tests, treatments, or procedures; and include estimates of expected health outcomes where such data exist. Patient-specific modifiers, comorbidities, and issues of patient preference that may influence the choice of tests or therapies are considered, as well as frequency of follow-up and cost-effectiveness. When available, information from studies on cost is considered; however, review of data on efficacy and outcomes constitutes the primary basis for preparing recommendations in this guideline.In analyzing the data, and developing recommendations and supporting text, the writing committee uses evidence-based methodologies developed by the Task Force.1 The Classification of Recommendation (COR) is an estimate of the size of the treatment effect, with consideration given to risks versus benefits, as well as evidence and/or agreement that a given treatment or procedure is or is not useful/effective or in some situations may cause harm; this is defined in Table 1. The Level of Evidence (LOE) is an estimate of the certainty or precision of the treatment effect. The writing committee reviews and ranks evidence supporting each recommendation, with the weight of evidence ranked as LOE A, B, or C, according to specific definitions that are included in Table 1. Studies are identified as observational, retrospective, prospective, or randomized, as appropriate. For certain conditions for which inadequate data are available, recommendations are based on expert consensus and clinical experience and are ranked as LOE C. When recommendations at LOE C are supported by historical clinical data, appropriate references (including clinical reviews) are cited if available.Table 1. Applying Classification of Recommendations and Level of EvidenceTable 1. Applying Classification of Recommendations and Level of EvidenceFor issues with sparse available data, a survey of current practice among the clinician members of the writing committee is the basis for LOE C recommendations and no references are cited.The schema for COR and LOE is summarized in Table 1, which also provides suggested phrases for writing recommendations within each COR.A new addition to this methodology is the separation of the Class III recommendations to delineate whether the recommendation is determined to be of “no benefit” or is associated with “harm” to the patient. In addition, in view of the increasing number of comparative effectiveness studies, comparator verbs and suggested phrases for writing recommendations for the comparative effectiveness of one treatment or strategy versus another are included for COR I and IIa, LOE A or B only.In view of the advances in medical therapy across the spectrum of cardiovascular diseases, the Task Force has designated the term guideline-directed medical therapy to represent optimal medical therapy as defined by ACC/AHA guideline (primarily Class I)–recommended therapies. This new term, guideline-directed medical therapy, is used herein and throughout subsequent guidelines.Therapies not available in the United States are discussed in the text without a specific COR. For studies performed in large numbers of subjects outside North America, each writing committee reviews the potential impact of different practice patterns and patient populations on the treatment effect and relevance to the ACC/AHA target population to determine whether the findings should inform a specific recommendation.The ACC/AHA practice guidelines are intended to assist clinicians in clinical decision making by describing a range of generally acceptable approaches to the diagnosis, management, and prevention of specific diseases or conditions. The guidelines attempt to define practices that meet the needs of most patients in most circumstances. The ultimate judgment about care of a particular patient must be made by the clinician and patient in light of all the circumstances presented by that patient. As a result, situations may arise in which deviations from these guidelines may be appropriate. Clinical decision making should involve consideration of the quality and availability of expertise in the area where care is provided. When these guidelines are used as the basis for regulatory or payer decisions, the goal should be improvement in quality of care. The Task Force recognizes that situations arise in which additional data are needed to inform patient care more effectively; these areas are identified within each respective guideline when appropriate.Prescribed courses of treatment in accordance with these recommendations are effective only if followed. Because lack of patient understanding and adherence may adversely affect outcomes, clinicians should make every effort to engage the patient’s active participation in prescribed medical regimens and lifestyles. In addition, patients should be informed of the risks, benefits, and alternatives to a particular treatment and should be involved in shared decision making whenever feasible, particularly for COR IIa and IIb, for which the benefit-to-risk ratio may be lower.The Task Force makes every effort to avoid actual, potential, or perceived conflicts of interest that may arise as a result of relationships with industry and other entities (RWI) among the members of the writing committee. All writing committee members and peer reviewers of the guideline are required to disclose all current healthcare-related relationships, including those existing 12 months before initiation of the writing effort.In December 2009, the ACC and AHA implemented a new RWI policy that requires the writing committee chair plus a minimum of 50% of the writing committee to have no relevant RWI (Appendix 1 includes the ACC/AHA definition of relevance). The Task Force and all writing committee members review their respective RWI disclosures during each conference call and/or meeting of the writing committee, and members provide updates to their RWI as changes occur. All guideline recommendations require a confidential vote by the writing committee and require approval by a consensus of the voting members. Members may not draft or vote on any recommendations pertaining to their RWI. Members who recused themselves from voting are indicated in the list of writing committee members, and specific section recusals are noted in Appendix 1. Authors’ and peer reviewers’ RWI pertinent to this guideline are disclosed in Appendixes 1 and 2. In addition, to ensure complete transparency, writing committee members’ comprehensive disclosure information—including RWI not pertinent to this document—is available as an online supplement. Comprehensive disclosure information for the Task Force is also available online at http://www.cardiosource.org/en/ACC/About-ACC/Who-We-Are/Leadership/Guidelines-and-Documents-Task-Forces.aspx. The ACC and AHA exclusively sponsor the work of the writing committee, without commercial support. Writing committee members volunteered their time for this activity. Guidelines are official policy of both the ACC and AHA.In an effort to maintain relevance at the point of care for clinicians, the Task Force continues to oversee an ongoing process improvement initiative. As a result, in response to pilot projects, several changes to this guideline will be apparent, including limited narrative text, a focus on summary and evidence tables (with references linked to abstracts in PubMed), and more liberal use of summary recommendation tables (with references that support the LOE) to serve as a quick reference.In April 2011, the Institute of Medicine released 2 reports: Finding What Works in Health Care: Standards for Systematic Reviews and Clinical Practice Guidelines We Can Trust.2,3 It is noteworthy that the Institute of Medicine cited ACC/AHA practice guidelines as being compliant with many of the proposed standards. A thorough review of these reports and of our current methodology is under way, with further enhancements anticipated.The recommendations in this guideline are considered current until they are superseded by a focused update, the full-text guideline is revised, or until a published addendum declares it out of date and no longer official ACC/AHA policy.Jeffrey L. Anderson, MD, FACC, FAHAChair, ACC/AHA Task Force on Practice Guidelines1. Introduction1.1. Methodology and Evidence ReviewThe recommendations listed in this document are, whenever possible, evidence based. An extensive evidence review was conducted, focusing on 2006 through October 2012 and selected other references through March 2014. The relevant data are included in evidence tables in the Online Data Supplement. Searches were extended to studies, reviews, and other evidence conducted in human subjects, published in English, and accessible through PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected databases relevant to this guideline. Key search words included but were not limited to the following: age, antiarrhythmic, atrial fibrillation, atrial remodeling, atrioventricular conduction, atrioventricular node, cardioversion, classification, clinical trial, complications, concealed conduction, cost-effectiveness, defibrillator, demographics, epidemiology, experimental, heart failure, hemodynamics, human, hyperthyroidism, hypothyroidism, meta-analysis, myocardial infarction, pharmacology, postoperative, pregnancy, pulmonary disease, quality of life, rate control, rhythm control, risks, sinus rhythm, symptoms, and tachycardia-mediated cardiomyopathy. Additionally, the writing committee reviewed documents related to atrial fibrillation (AF) previously published by the ACC and AHA. References selected and published in this document are representative and not all-inclusive.To provide clinicians with a comprehensive set of data, whenever deemed appropriate or when published, the absolute risk difference and number needed to treat or harm are provided in the guideline or data supplement, along with confidence intervals (CI) and data related to the relative treatment effects such as the odds ratio (OR), relative risk (RR), hazard ratio, or incidence rate ratio.1.2. Organization of the Writing CommitteeThe 2014 AF writing committee was composed of clinicians with broad expertise related to AF and its treatment, including adult cardiology, electrophysiology, cardiothoracic surgery, and heart failure (HF). The writing committee was assisted by staff from the ACC and AHA. Under the guidance of the Task Force, the Heart Rhythm Society was invited to be a partner organization and provided representation. The writing committee also included a representative from the Society of Thoracic Surgeons. The rigorous methodological policies and procedures noted in the Preamble differentiate ACC/AHA guidelines from other published guidelines and statements.1.3. Document Review and ApprovalThis document was reviewed by 2 official reviewers each nominated by the ACC, AHA, and Heart Rhythm Society, as well as 1 reviewer from the Society of Thoracic Surgeons and 43 individual content reviewers (from the ACC Electrophysiology Section Leadership Council, ACC Adult Congenital and Pediatric Cardiology Section Leadership Council, ACC Association of International Governors, ACC Heart Failure and Transplant Section Leadership Council, ACC Imaging Section Leadership Council, ACC Interventional Section Leadership Council, ACC Surgeons' Council, and the Heart Rhythm Society Scientific Documents Committee). All information on reviewers’ RWI was distributed to the writing committee and is published in this document (Appendix 2).This document was approved for publication by the governing bodies of the ACC, AHA, and Heart Rhythm Society and endorsed by the Society of Thoracic Surgeons.1.4. Scope of the GuidelineThe task of the 2014 writing committee was to establish revised guidelines for optimum management of AF. The new guideline incorporates new and existing knowledge derived from published clinical trials, basic science, and comprehensive review articles, along with evolving treatment strategies and new drugs. This guideline supersedes the “ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation”4 and the 2 subsequent focused updates from 2011.5,6 In addition, the ACC, AHA, American College of Physicians, and American Academy of Family Physicians submitted a proposal to the Agency for Healthcare Research and Quality to perform a systematic review on specific questions related to the treatment of AF. The data from that report were reviewed by the writing committee and incorporated where appropriate.7a, 7bThe 2014 AF guideline is organized thematically, with recommendations, where appropriate, provided with each section. Some recommendations from earlier guidelines have been eliminated or updated as warranted by new evidence or a better understanding of earlier evidence. In developing the 2014 AF guideline, the writing committee reviewed prior published guidelines and related statements. Table 2 lists these publications and statements deemed pertinent to this effort and is intended for use as a resource.Table 2. Associated Guidelines and StatementsTitleOrganizationPublication Year/ReferenceGuidelines Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7)NHLBI20038 Assessment of Cardiovascular Risk in Asymptomatic AdultsACC/AHA20109 Coronary Artery Bypass Graft SurgeryACC/AHA201110 Hypertrophic CardiomyopathyACC/AHA201111 Percutaneous Coronary InterventionACC/AHA/SCAI201112 Secondary Prevention and Risk Reduction Therapy for Patients With Coronary and Other Atherosclerotic Vascular DiseaseAHA/ACC201113 Atrial Fibrillation*CCS201214 Atrial FibrillationESC201215 Stable Ischemic Heart DiseaseACC/AHA/ACP/AATS/PCNA/SCAI/STS201216 Antithrombotic TherapyACCP201217 Device-Based TherapyACC/AHA/HRS201218 Heart FailureACC/AHA201319 ST-Elevation Myocardial InfarctionACC/AHA201320 Unstable Angina/Non-ST-Elevation Myocardial InfarctionACC/AHA201421 Valvular Heart DiseaseAHA/ACC201422 Assessment of Cardiovascular RiskACC/AHA201323 Lifestyle Management to Reduce Cardiovascular RiskAHA/ACC201324 Management of Overweight and Obesity in AdultsAHA/ACC/TOS201325 Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in AdultsACC/AHA201326Statements Treatment of Atrial FibrillationAHRQ20137a,7b Oral Antithrombotic Agents for the Prevention of Stroke in Nonvalvular Atrial Fibrillation: A Science Advisory for Healthcare ProfessionalsAHA/ASA201227 Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Patient Selection, Procedural Techniques, Patient Management and Follow-Up, Definitions, Endpoints, and Research Trial DesignHRS/EHRA/ECAS201228*Includes the following sections: Catheter Ablation for AF/Atrial Flutter; Prevention and Treatment of AF Following Cardiac Surgery; Rate and Rhythm Management; Prevention of Stroke and Systemic Thromboembolism in AF and Flutter; Management of Recent-Onset AF and Flutter in the Emergency Department; Surgical Therapy; The Use of Antiplatelet Therapy in the Outpatient Setting; and Focused 2012 Update of the CCS AF Guidelines: Recommendations for Stroke Prevention and Rate/Rhythm Control.AATS indicates American Association for Thoracic Surgery; ACC, American College of Cardiology; ACCP, American College of Chest Physicians; ACP, American College of Physicians; AF, atrial fibrillation; AHA, American Heart Association; AHRQ, Agency for Healthcare Research and Quality; ASA, American Stroke Association; CCS, Canadian Cardiology Society; ECAS, European Cardiac Arrhythmia Society; EHRA, European Heart Rhythm Association; ESC, European Society of Cardiology; HRS, Heart Rhythm Society; JNC, Joint National Committee; NHLBI, National Heart, Lung, and Blood Institute; PCNA, Preventive Cardiovascular Nurses Association; SCAI, Society for Cardiovascular Angiography and Interventions; STS, Society of Thoracic Surgeons; and TOS, The Obesity Society.2. Background and PathophysiologyAF is a common cardiac rhythm disturbance that increases in prevalence with advancing age. Approximately 1% of patients with AF are <60 years of age, whereas up to 12% of patients with AF are 75 to 84 years of age.29 More than one third of patients with AF are ≥80 years of age.30,31 In the United States, the percentage of Medicare fee-for-service beneficiaries with AF in 2010 was reported as 2% for those <65 years of age and 9% for those ≥65 years of age.32 For individuals of European descent, the lifetime risk of developing AF after 40 years of age is 26% for men and 23% for women.33 In African Americans, although risk factors for AF are more prevalent, incidence of AF appears to be lower.34 AF is often associated with structural heart disease and other co-occurring chronic conditions (Table 3; see also http://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/Chronic-Conditions/Downloads/2012Chartbook.pdf). The mechanisms causing and sustaining AF are multifactorial; AF can be complex and difficult for clinicians to manage. Symptoms of AF range from nonexistent to severe. Frequent hospitalizations, hemodynamic abnormalities, and thromboembolic events related to AF result in significant morbidity and mortality. AF is associated with a 5-fold increased risk of stroke,35 and stroke risk increases with age.36 AF-related stroke is likely to be more severe than non–AF-related stroke.37 AF is also associated with a 3-fold risk of HF38–40 and a 2-fold increased risk of both dementia41 and mortality.35 In the United States, hospitalizations with AF as the primary diagnosis total >467 000 annually, and AF is estimated to contribute to >99 000 deaths per year. Patients with AF are hospitalized twice as often as patients without AF and are 3 times more likely to have multiple admissions; 2.1% of patients with AF died in the hospital, compared with 0.1% without it.42,43 AF is also expensive, adding approximately $8700 per year (estimate from 2004 to 2006) for a patient with AF compared with a patient without AF. It is estimated that treating patients with AF adds $26 billion to the US healthcare bill annually. AF affects between 2.7 million and 6.1 million American adults, and that number is expected to double over the next 25 years, adding further to the cost burden.42,43Table 3. 10 Most Common Comorbid Chronic Conditions Among Medicare Beneficiaries With AFBeneficiaries ≥65 y of Age (N=2 426 865) (Mean Number of Conditions=5.8; Median=6)Beneficiaries <65 y of Age (N=105 878) (Mean Number of Conditions=5.8; Median=6)N%N%Hypertension2 015 23583.0Hypertension85 90881.1Ischemic heart disease1 549 12563.8Ischemic heart disease68 28964.5Hyperlipidemia1 507 39562.1Hyperlipidemia64 15360.6HF1 247 74851.4HF62 76459.3Anemia1 027 13542.3Diabetes mellitus56 24653.1Arthritis965 47239.8Anemia48 25245.6Diabetes mellitus885 44336.5CKD42 63740.3CKD784 63132.3Arthritis34 94933.0COPD561 82623.2Depression34 90033.0Cataracts546 42122.5COPD33 21831.4AF indicates atrial fibrillation; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; and HF, heart failure.Reproduced with permission from the Centers for Medicare & Medicaid Services.44AF Web-based tools are available, including several risk calculators and clinical decision aids (http://www.cardiosource.org/Science-And-Quality/Clinical-Tools/Atrial-Fibrillation-Toolkit.aspx); however, these tools must be used with caution because validation across the broad range of patients with AF encountered in clinical practice is incomplete.2.1. Definitions and Pathophysiology of AFAF is a supraventricular tachyarrhythmia with uncoordinated atrial activation and consequently ineffective atrial contraction.4,28,30 Characteristics on an electrocardiogram (ECG) include 1) irregular R-R intervals (when atrioventricular [AV] conduction is present), 2) absence of distinct repeating P waves, and 3) irregular atrial activity.Hemodynamic consequences of AF can result from a variable combination of suboptimal ventricular rate control (either too rapid or too slow), loss of coordinated atrial contraction, beat-to-beat variability in ventricular filling, and sympathetic activation.45–47 Consequences for individual patients vary, ranging from no symptoms to fatigue, palpitations, dyspnea, hypotension, syncope, or HF.48 The most common symptom of AF is fatigue. The appearance of AF is often associated with exacerbation of underlying heart disease, either because AF is a cause or consequence of deterioration or because it contributes directly to deterioration.49,50 For example, initially asymptomatic patients may develop tachycardia-induced ventricular dysfunction and HF (tachycardia-induced cardiomyopathy) when the ventricular rate is not adequately controlled.51,52 AF also confers an increased risk of stroke and/or peripheral thromboembolism owing to the formation