[Myocarditis simulating myocardial infarction].

Acute myocarditis caused by infectious mononucleosis simulated myocardial infarction, initially the quantitative and qualitative blood picture was normal. Repeated blood and serological studies confirmed the diagnosis, which was altered by acute porphyria caused by infection. In each case of young patients with myocardial infarction and in older patient with coexisting infectious symptoms, myocarditis must be considered. Since the cardiac manifestation may precede the infectious disease symptoms, repeating the necessary examinations may be mandatory.