Although previous studies including endurance athletes after marathon running 
have demonstrated biochemical evidence of cardiac injury and have correlated 
these findings with echocardiographic evidence of cardiac dysfunction, 
particularly of the right ventricle, a study of marathon athletes incorporating 
biomarkers, echocardiography, and cardiac magnetic resonance (CMR) imaging has 
not been performed to date. The aim of this study was to demonstrate the cardiac 
changes associated with participation in a marathon using serial cardiac 
biomarkers, echocardiography, and CMR imaging. Fourteen participants (mean age 
33 +/- 6 years, 8 men) completed the full marathon. Myoglobin, creatine kinase, 
and troponin T were elevated in all athletes after the race. There was a strong 
linear correlation between right ventricular (RV) fractional area change as 
assessed by echocardiography and the RV ejection fraction as assessed by CMR 
imaging (r = 0.96) after the marathon. RV function, using echocardiography, 
transiently decreased from before to after the race (RV fractional area change 
43 +/- 4% vs 33 +/- 5%, p <0.05). There were also postrace changes in left 
ventricular and RV diastolic filling. Although RV systolic changes were 
transient, left ventricular and RV diastolic abnormalities persisted up to 1 
week after the marathon. No evidence of delayed enhancement of the left 
ventricular myocardium was found on CMR imaging, suggesting that the increase in 
cardiac biomarkers after the marathon may not have be due to myocardial 
necrosis. In conclusion, RV systolic dysfunction transiently occurs after a 
marathon and has been validated for the first time by CMR imaging. The increase 
in cardiac troponin after marathon running is likely due to the cytosolic 
release of the biomarker, not to the true breakdown of the myocyte, as confirmed 
by delayed enhancement CMR imaging.