Electrocardiogram and echocardiogram findings in runners completing a half marathon

The purpose of this study was to prospectively evaluate electrocardiograms (ECGs) before and after running a half marathon to characterize the changes that occur after exertion. Echocardiograms were also done postrace on selected runners.

Volunteer runners older than 18 years completed a questionnaire detailing demographic and medical history. Prerace ECGs were performed at a prerace symposium and postrace ECGs were performed within 15 minutes of the participants' completion of the race. Echocardiograms were performed on a random sampling of runners who were judged to have abnormal or changed postrace ECGs.

Eighty-seven runners were enrolled and completed the study. There were 46 males (53%) and 41 females (47%). Fifty-four (62%) runners had changes noted in their ECGs. The most common changes noted were atrial enlargement (37 runners). Other abnormalities seen on the ECGs included new conduction abnormalities, new Q waves, nonspecific ST/T-wave changes, and resolution of previous abnormalities that were seen on initial ECG. There was no statistically significant difference between runners with ECG changes and runners without ECG changes when comparing sex, age, previous marathon experience, exercise, history of exercise-induced chest pain, medical history, and family history of heart disease. Twenty runners with changed or abnormal postrace ECGs had postrace echocardiograms, and 8 were abnormal. Of the abnormal echocardiograms, 2 runners had normal but changed postrace ECGs and 4 runners had abnormalities that were inconsistent with what was seen on ECG.

Our study suggests that ECG abnormalities and changes can occur in distance runners, but their significance is unclear.