Inflammation and Atrial Remodeling After a Mountain Marathon
With the increasing popularity of long-distance sports, endurance athletes are at risk for developing atrial arrhythmias, especially fibrillation. Although the pathophysiology of exercise-induced atrial fibrillation is multifactorial, the authors of this study hypothesize that atrial remodeling and acute inflammation play a key role. The investigators performed a longitudinal study on elite runners at the 2010 Jungfrau Marathon, a popular trail marathon in the Swiss Alps. Male participants 20 to 40 years old who had completed the 2009 Jungfrau Marathon and did not have a personal or family history of cardiac disease were enrolled. Subjects had the following tests performed: electrocardiogram with signal average P-wave duration (SAPWD), transthoracic echocardiography, 24-hour Holter monitor, cardiopulmonary exercise testing, 24-hour blood pressure measurements, and blood laboratory analysis. A combination of these various tests was performed at baseline, immediately after the race, and 1 and 8 days after the race.
A total of 10 participants were enrolled with similar baseline characteristics. Although the left and right atrial volumes remained unchanged, the SAPWD increased significantly directly after the race but returned to baseline during follow-up. The cardiac biomarkers proatrial natriuretic peptide (proANP) and troponin also increased immediately after the race but decreased to baseline, thought to be caused by a transient increase in atrial stretch and reversible myocyte membrane leak. The C-reactive protein (CRP) increased 1 day after the race but decreased to baseline 8 days later.
By using the SAPWD as a surrogate marker to represent atrial edema and remodeling, the authors proposed a transient and significant atrial conduction delay after the trail marathon. In conclusion, the authors believe their data represent an acute inflammatory process that plays an important role in atrial remodeling and could predispose endurance athletes to atrial fibrillation. Future studies would include structural cardiac imaging, such as cardiac magnetic resonance imaging. Study limitations include small sample size, influence of high altitude, and the use of SAPWD as an indirect measure of myocardial edema.
(Scand J Med Sci Sports. 2012 Dec 18 [Epub ahead of print]) M Wilhelm, T Zueger, S De Marchi, et al.