Background Subepicardial delayed gadolinium enhancement (DGE) patches without underlying cardiomyopathy is poorly understood. It is often reported as the result of prior silent myocarditis. Its prognostic relevance in asymptomatic athletes is unknown; therefore, medical clearance for competitive sports participation is debated. This case series aims to relate this pattern of DGE in athletes to outcome.

Methods We report on seven young asymptomatic athletes with isolated subepicardial DGE detected during workup of abnormalities on their regular screening examination, that is, pathological T-wave inversions on ECG (n=4) or ventricular arrhythmias on exercise test (n=3). All underwent a comprehensive initial investigation in order to assess left ventricular (LV) function at rest and exercise (exercise cardiac MRI and/or exercise echocardiography) and occurrence of arrhythmias (exercise test, 24 h-ECG Holter, electrophysiological study). All underwent a careful follow-up with biannual evaluation.

Results All athletes had extensive subepicardial DGE (12.0±4.8% of LV mass), predominantly in the lateral wall. Three athletes had non-sustained ventricular arrhythmias, whereas two of them had LV ejection fraction <50% at rest with no contractile reserve at exercise. During a follow-up of 3.0±1.5 years in the four remaining athletes, two had symptomatic ventricular tachycardia and one demonstrated progressive LV dysfunction. Hence, six of seven athletes had to be excluded from competitive sports participation.

Conclusions Isolated large areas of subepicardial DGE in an asymptomatic athlete are not benign and require a careful evaluation at exercise and a strict follow-up. These findings question whether extreme exercise during silent myocarditis may facilitate fibrosis generation and adverse remodelling.