Although atrial fibrillation (AF) is considered the most common arrhythmia in clinical practice, its prevalence is relatively low in the young and middle-aged, ranging from 0.5 % in men below 40 years to 1 % by 60 years.1,2 Regular exercise is proposed as a powerful tool for the primary and secondary prevention of cardiovascular disease, reducing most of the risk factors that predispose to AF, such as hypertension, diabetes mellitus, coronary artery disease and obesity.3,4 However, there is growing evidence that long-term endurance exercise may increase the risk of developing AF, with a reported 2-10 times greater prevalence in athletes and those who are involved in long-term sport participation.
5Why athletes should be susceptible to AF is an issue of ongoing debate. Several mechanisms underlying the association between exercise and AF have been proposed but they remain speculative.It is of interest that adaptations such as sinus bradycardia and atrioventricular node disturbances, which are generally considered benign and reversible after a short period of detraining, have been considered by some investigators as a reason for AF development in elderly athletes. 6 It is clear that AF in athletes has some differences in cause, clinical presentation and treatment strategies compared with the general population. The aim of this short review is to present the existing data about the epidemiology of AF in athletes and those engaged in long-term endurance sport practice, to analyse the pathophysiological mechanisms that connect AF with exercise, and finally to discuss the existing treatment options.
Prevalence and Incidence of Atrial Fibrillation in Endurance Sport Practice and in Vigorous Physical ActivityThe prevalence of AF in the athletic community varies considerably dependent on the age and the number of years of training of the subjects. It is essential to make a distinction between studies including young athletes with only a few years of training and those with middle-aged or older individuals practising sports for many years.Whereas the incidence of AF in young athletes appears similar to that observed in the general population, in older athletes an increased incidence of AF is reported. 6,[8][9][10][11][12][13][14][15] Furlanello et al. 16 and Pelliccia et al. 17 reported a low rate of AF (0.2 % and 0.3 %, respectively), no different from that observed in the general population. However, both studies included exclusively young athletes with relatively fewer years of training. In contrast, several other studies of middle-aged athletes, who were engaged in sport training for many years, demonstrated an increased prevalence of AF compared with the rest of the population (see Table 1). A common characteristic among all these studies was that the participating athletes were predominately male and they were involved in endurance sports. The prevailing pattern of AF was the so-called vagal lone AF, as it was usually encountered in relatively young individuals (<60 years old) without clinical or echocardiographic e...