Interestingly, an unusually high incidence of AF has been noted in healthy endurance athletes. While myocardial fibrosis is known to be present in this population, there are currently no standard techniques used to specifically quantify left atrial (LA) fibrosis. Evaluating LA fibrosis could potentially help predict an endurance athlete’s risk of developing atrial arrhythmia.
Using late gadolinium-enhancement (LGE) MRI, a team from the University of Utah, Salt Lake City, Utah, USA, quantified the degree of LA fibrosis in 16 endurance athletes compared with 20 healthy controls, and the results were presented yesterday by Doctor David Peritz (Abstract P4692). All participants underwent cardiac MRI with 3D visualisation using processing software.
Although the endurance athletes tended to have a lower BMI and were younger than the controls (all athletes were older than 35 years of age), they had a greater mean LA fibrosis score compared with the controls: 13.7% ± 5.4 versus 11.8% ± 7.3, respectively. Dr. Peritz says that, “In our study, endurance athletes who had consistently participated in at least 10 years of competitive sports and actively trained for at least 10 hours per week had a significantly greater degree of LA fibrosis than the controls.” He adds, “What is more, being an endurance athlete appears to have a greater impact on the degree of fibrosis than any of the usual comorbidities linked to LA fibrosis, such as diabetes, hypertension and tobacco use.”
While there is a significant correlation between endurance training and the degree of LA fibrosis, as detected on cardiac MRI, the researchers caution that the clinical significance of this finding is unclear. They suggest that the increased LA fibrosis in endurance athletes could explain the higher incidence of atrial arrhythmia, including AF, in this population.