Epidemiology of atrial fibrillation

Abstract

Atrial fibrillation (AF) is the most common arrhythmia and is characterized by an uncontrolled atrial activity with consequent deterioration of cardiac mechanical function. Besides being associated to an increased risk of death, two major complications of AF determine its clinical importance: stroke and congestive heart failure. The incidence of AF in the general adult population is about 2 per 1,000 persons /year and its prevalence about 1%. These values steeply increase with old age, implicating a continuous rise in the prevalence of AF, considering the global population aging. Stroke represents the world's third leading cause of death and is associated with high rates of morbidity. The etiological investigation, particularly for ischemic stroke, becomes important not only to plan secondary prevention and to predict prognosis, but also to devise strategies for primary prevention. The proportion of cardioembolic strokes according to the TOAST classification in population-based stroke incidence studies ranges from 15% to 34%, the majority caused by AF. There was no apparent increase in these proportions according to the study year. The heterogeneity of values may be due to the study characteristics and not to a real variation in different causal mechanisms, since there is a widespread variation in the proportion of infarcts with undetermined etiology. Considering the population aging and the systematic identification of this arrhythmia, an increase in the incidence and prevalence of AF is expected. On the other hand, the advent of stratification risk scores for stroke combined with an appropriate prevention strategy for each patient, including the use of new anticoagulants, may prevent the increase of cerebral infarction caused by embolism, secondary to AF.