The changing epidemiology and natural history of nonvalvular atrial fibrillation: clinical implications.

The growing "epidemic" of non-valvular atrial fibrillation (NVAF) with its associated morbidity and mortality intersects with a number of conditions including aging, thromboembolism, stroke, congestive heart failure, hypertension, and perhaps the metabolic syndrome and inflammation.In the USA approximately 2.3 million people currently have NVAF and estimates based upon the United States census and the aging of the population suggests that this will be 3.3 million by 2020 and 5.6 million by 2050. This may be a serious underestimate since recent data from Rochester, Minnesota have demonstrated an almost threefold increase in the prevalence over the last three decades after adjustment for age. The explanation is probably multifactorial but the socioeconomic implications of this phenomenon are enormous and sobering.Ongoing efforts towards understanding atrial fibrillation are driven, in part, by the concept that atrial fibrillation may in most patients be the consequence of a systemic condition, in which reduced vascular compliance, atherosclerosis, obesity, and inflammation are primary causal factors. These epidemiological investigations need to be carried out in association with studies aimed at defining the molecular genetics of atrial fibrillation which hopefully will provide more insights into the structural and electrical phenotypes resulting from genetic mutations and their interactions with the environment.