A. Epidemiology update: 1. Scope of the problem Nonvalvular AF: Issues and challenges Content Points: For the purposes of this slide kit, the term "AF" (atrial fibrillation) refers to arrhythmia not related to valvular heart disease (nonvalvular AF). AF is a supraventricular tachycardia characterized by uncoordinated atrial function.1 It may be isolated or associated with atrial flutter or atrial tachycardia. The atrial rate is 240 to 320 beats per minute (bpm). Two-to-one atrioventricular block is common, producing a ventricular rate of 120 to 160 bpm. This arrhythmia, the most commonly encountered in clinical practice and a major cause of cardioembolic stroke, is associated with a number of ongoing issues and related challenges. These are summarized on the slide. This slide kit addresses areas where progress is occurring, including mechanisms of AF-related stroke, risk stratification, and the role of anticoagulant therapy. 1Fuster V, Rydén LE, Asinger RW, Cannom DS, Crijns HJ, Frye RL, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force of Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation). J Am Coll Cardiol. 2001;38:1231-1265.

ATRIA: Prevalence of AF by age and sex Content Points: The AnTicoagulation and Risk factors In Atrial fibrillation (ATRIA) study was a cross-sectional prevalence study in adults who were enrolled in a large California health maintenance organization (Kaiser Permanente of Northern California).1 In the study population of 1.89 million, a diagnosis of AF was entered in the medical records of 17,974 patients (0.95%) between July 1, 1996 and December 31, 1997. The prevalence of AF was greater in men than in women, and increased with age in both groups.   1Go AS, Hylek EM, Phillips KA, Chang Y, Henault LE, Selby JV, Singer DE. Prevalence of diagnosed atrial fibrillation in adults: National implications for rhythm management and stroke prevention: The AnTicoagulation and Risk factors In Atrial fibrillation (ATRIA) study. JAMA.2001;285:2370-2375.

ATRIA: Projected number of patients with AF Content Points: The ATRIA investigators estimated that 2.08 million Americans had AF during the period of cohort assembly and that this would rise to 5.61 million by 2050, an increase of approximately 2.5-fold.1 This increase reflects the projected increase in elderly individuals in the US population.   1Go AS, Hylek EM, Phillips KA, Chang Y, Henault LE, Selby JV, Singer DE. Prevalence of diagnosed atrial fibrillation in adults: National implications for rhythm management and stroke prevention: The AnTicoagulation and Risk factors In Atrial fibrillation (ATRIA) study. JAMA. 2001;285:2370-2375.

Hospitalizations for AF are increasing Content Points: Wattigney et al used data from the National Hospital Discharge Survey to study US trends in hospitalization for AF between 1985 and 1999.1 In this study, the investigators used ICD-9-CM diagnosis codes 42731 and 42732 to identify patients with AF. These codes include both AF and atrial flutter. Total hospitalizations for AF as the principal diagnosis increased from 154,086 to 376,487 (144% change). Hospitalizations for AF as a principal or secondary diagnosis followed a similar trend: 787,750 to 2,283,763 (190% change). As shown, while rates for individuals aged <64 years remained relatively level, the rates for individuals aged >65 years have risen.   1Wattigney WA, Mensah GA, Croft JB. Increasing trends in hospitalization for atrial fibrillation in the United States, 1985 through 1999: Implications for primary prevention. Circulation. 2003;108:711-716.

Mortality and AF Content Points: Wolf et al conducted a prospective cohort study of 26,753 hospitalized patients with cardiovascular disease; 13,558 patients also had AF; 13,195 patients did not.1 The slide summarizes mortality rates by age and sex during the 3-year study period. Patients with AF had significantly higher mortality rates than matched patients without AF.   1Wolf PA, Mitchell JB, Baker CS, Kannel WB, D'Agostino RB. Impact of atrial fibrillation on mortality, stroke, and medical costs. Arch Intern Med. 1998;158:229-234.