With a substantial impact on morbidity and mortality, the growing "epidemic" of atrial
fibrillation (AF) intersects with a number of conditions, including aging, thromboembolism,
hemorrhage, hypertension and left ventricular dysfunction. Currently, the epidemiology
and natural history of AF govern all aspects of its clinical management. The ongoing
global investigative efforts toward understanding AF are also driven by epidemiologic
findings. New developments, by affecting the natural history of the disease, could
eventually alter the nature of decision making in patients with AF. The crucial issue
of rate versus rhythm control awaits completion of the AF Follow-up Investigation
of Rhythm Management trial. The processes of electrical and structural remodeling
that perpetuate AF appear to be reversible. In the era of functional genomics, the
molecular basis of this ubiquitous arrhythmia is in the process of being defined.
Unraveling the molecular genetics of AF might provide new insights into the structural
and electrical phenotypes resulting from genetic mutations and, as such, new approaches
to treatment of this arrhythmia at the ion channel and cellular levels. Thus, current
adverse trends are superimposed on a background of a rapidly developing knowledge
base and potentially exciting new therapeutic options. Consequently, an understanding
of the epidemiology and natural history of AF is crucial to the future allocation
of resources and the utilization of an expanding range of therapies aimed at reducing
the impact of this disease on a changing patient population.