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Exercise-Induced Second-Degree Atrioventricular Block in Endurance Athletes


Medicine & Science in Sports & Exercise: March 2013 - Volume 45 - Issue 3 - p 411–414
doi: 10.1249/MSS.0b013e318276c9a4
Clinical Sciences

ABSTRACT Training induces volume- and time-dependent morphological and functional changes in the heart. Heart rhythm disorders, such as atrial arrhythmia (including atrial fibrillation and atrial flutter), are a well-established consequence of such long-term endurance practice. Although resting bradycardia and first-degree atrioventricular persist in veteran athletes, a higher conduction system impairment has never been reported neither at rest nor during exercise. We report here two cases of Type II second-degree atrioventricular block occurring during exercise in middle-age well-trained athletes. Because animal and human studies suggest that a progressive myocardial fibrosis could explain such phenomenon, long-term training could also have consequences on the conduction pathways.

Service de Physiologie et d’Explorations Fonctionnelles, CHU de Strasbourg, Strasbourg, FRANCE

Address for correspondence: Stéphane Doutreleau, M.D., Ph.D., Service de Physiologie et d’Explorations Fonctionnelles, CHU de Strasbourg—NHC, 1 place de l’hôpital, 67091 Strasbourg Cedex, France; E-mail:

Submitted for publication April 2012.

Accepted for publication September 2012.

© 2013 American College of Sports Medicine