Acute viral infections can lead to heart inflammation, including acute myocarditis. We report the first case of myopericarditis in a young immunocompetent adult, in the context of recent Epstein-Barr virus infection. Clinical presentation was common acute pericarditis, but with risk biomarkers: high troponin I levels and multiple inflammation-compatible images on MRI. Diagnosis of myopericarditis was established, and then hospitalization was necessary. Clinical electrocardiographic settings and MRI are shown; EBV cardiac effects are discussed.