Atrial Fibrillation Pathophysiology and Prognosis

Atrial fibrillation (AF) is the most common sustained arrhythmia and is characterized by ineffective atrial contractions and often rapid ventricular response rates. It has been recognized that the risk of AF increases with age and the rise in AF incidence in recent decades is at least partly accounted for by the aging population in addition to the increase in other risk factors, including obesity.1,2 The global estimated prevalence of AF was u003e33 million in 2010,3 and projections indicate that its incidence and prevalence could potentially increase u003e2.5-fold by 2030.4 Although aging, hypertension, body mass index, structural heart disease, heart failure, and pulmonary disease are recognized clinical risk factors for the development of AF,5,6 advances in cardiovascular imaging, including novel echocardiographic techniques, cardiac MRI (CMR), computed tomography (CT), and positron emission tomography, have provided novel insights into AF pathogenesis, prediction, and natural history.Despite the use of novel imaging technologies and the use of sophisticated invasive ablative techniques and newer anticoagulation strategies, AF still comprises a considerable public health burden and results in major morbidity and expenditures.7,8 Thromboembolism and its sequelae account for much of this burden. Ineffective atrial contraction results in decreased flow and stagnation of blood in atrial structures, primarily the left atrial (LA) appendage (LAA), and AF itself may represent an inflammatory and procoagulable state, further contributing to thromboembolism pathogenesis.9,10 In addition, one has to take into account the company it keeps in that AF is associated with a significant number of comorbidities, which may independently contribute to thromboembolism and other adverse outcomes. Given this expanding burden and the challenges in developing effective management strategies for AF and its complications, workshops of the American Heart Association and the National Heart, Lung, and Blood Institute …