Atrial fibrillation: current understandings and research imperatives. The National Heart, Lung, and Blood Institute Working Group on Atrial Fibrillation.

Atrial fibrillation is the most common sustained cardiac arrhythmia encountered in clinical practice. Atrial fibrillation increases with age and is relatively common (> 5%) in patients > 69 years old. Despite this, our understanding of the underlying electrophysiologic mechanisms and the optimal management remains incomplete. This arrhythmia is seen most frequently in association with coronary disease or hypertension, but it is also frequently a consequence of rheumatic heart disease. The mechanism of atrial fibrillation requires further elucidation, but the most widely accepted hypothesis is a multiple reentrant wavelet mechanism. The treatment of atrial fibrillation is undertaken to reduce the risk of stroke or systemic embolus, to control palpitation or other symptoms or to improve exercise tolerance or treat pulmonary congestion. This report is a discussion of the epidemiology of atrial fibrillation and of the etiology, mechanism, management and future research directions in the study of this arrhythmia.