Prevalence and pattern of focal and potential diffuse myocardial fibrosis in male and female marathon runners using contrast-enhanced cardiac magnetic resonance.

• A high frequency of myocardial fibrosis was found in marathon runners. • Myocardial fibrosis occurred typically in male runners and was typically non-ischemic. • Higher training load could be one cofactor in the genesis of myocardial fibrosis in marathon runners.