Courtesy of WOWSA, Huntington Beach, California.
Endurance Sport Practice as a Risk Factor for Atrial Fibrillation and Atrial Flutter
The typical clinical profile of sport-related AF or atrial flutter is a middle-aged man (in his forties or fifties) who has been involved in regular endurance sport practice since his youth (soccer, cycling, jogging, and swimming), and is still active. This physical activity is his favourite leisure time activity and he is psychologically very dependent on it. The AF is usually paroxysmal with crisis, initially very occasional and self limited, and progressively increasing in duration. Characteristically, AF episodes occur at night or after meals. As many as 70% of patients may suffer predominantly vagal AF. They almost never occur during exercise. This makes the patient reluctant to accept a relationship between the arrhythmia and sport practice, particularly since his physical condition is usually very good. The crises typically become more frequent and prolonged over the years and AF becomes persistent. Progression to permanent AF has been described by Hoogsteen et al. in 17% of individuals in an observational series. In the GIRAFA study, 43% presented persistent AF. The AF crisis frequently coexists with common atrial flutter in many patients, as previously discussed
Although data on the reversibility of arrhythmia upon sport cessation are scarce, Furlanello et al. have described a good response to sport abstinence in top-level athletes with AF. Our observations, although not systematic, suggest that limiting physical activity seems to significantly reduce the number of crises, particularly in those with recent onset and minimally dilated atrium. However, these patients are very dependent on physical activity and it is difficult for them to follow this advice. Previous studies have demonstrated the reversibility of hypertrophic changes at the ventricular level in the hearts of athletes. Biffi et al. also showed a very significant decrease in ventricular ectopy upon sport cessation. Therefore, while awaiting more definitive data, it seems advisable to significantly reduce endurance sport practice in these cases.
The possible long-term role of drugs (ACE inhibitors, angiotensin inhibitors, or beta-blockers) in preventing cardiac hypertrophy remains to be elucidated, although angiotensin blockers do seem to play a role in improving the results of cardioversion or AF ablation. In terms of arrhythmia prevention, patients with recurrent episodes have been treated with flecainide and diltiazem, preventing 1:1 atrial flutter secondary to flecainide with good results. Some of them had undergone AF ablation with a success rate similar to patients not involved in endurance sport practice (authors’ unpublished observations). In patients with predominant atrial flutter, ablation of the flutter is frequently associated with a higher incidence of AF recurrences, as pointed out by Heidbuchel et al. A recent study by Furlanello et al. described a highly successful ablation, with 90% success after a mean of two ablation procedures in a series of 20 athletes, without major complications. Apparently, the goal of the ablation was to allow rather veteran athletes (44 ± 13 years) to re-initiate their competitive activity. The reported series may represent a selected series of patients, since most of them presented exercise-induced AF, in contrast with the reported prevalence of vagal AF among endurance athletes. Although ablation seems to be quite effective, endurance sport cessation associated with drug therapy seems to us a more suitable approach as an initial therapy, particularly in non-professional, veteran athletes.
Vigorous physical activity, whether related to long-term endurance sport practice or to occupational activities, seems to increase the risk for recurrent AF. The underlying mechanisms remain to be elucidated, although structural atrial changes (dilatation and fibrosis) are probably present. There is a relationship between accumulated hours of practice and AF risk. Further studies are needed to clarify whether a threshold limit for the intensity and duration of physical activity may prevent AF, without limiting the cardiovascular benefits of exercise.
Europace. 2009;11(1):11-17. © 2009 Oxford University Press
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