RESUMO
Actinomycosis infection can involve most part of the human body including mouth, cervicoface, chest, abdomen and pelvis. Cardiac involvement occurs in less than 2 percent of the infection of actinomyces israelii and pericardial involvement is rare. 34 year male was admitted because of chest pain and general weakness for several months. Echocardiography revealed akinesia of apex suggesting myocardial infarction and large pericardial effusion. Under the impression of pericardial effusion from tuberculosis infection, the patient was started on anti-tuberculosis medicine. Pericardial window operation with pericardial biopsy was performed 7 days later when the patient failed to show a significant improvement. Pericardial biopsy confirmed actinomycosis infection. During admission, the patient had a cerebral infarction with left hemiparesis. The patient was treated with high dose penicillin and improved symptomatically. Echocardiography showed resolution of pericardial effusion.