Eosinophilic myocarditis associated with dense deposits of eosinophil cationic protein (ECP) in endomyocardium with high serum ECP

A case of eosinophilic myocarditis following high serum levels of eosinophi l cationic protein (ECP) is described. A 27 year old woman was admitted wit h New York Heart Association (NYHA) class III congestive heart failure. A h aematological study showed hypereosinophilia with degranulation and vacuole s; the total eosinophil count was 7980/ml and the ECP serum concentration w as noticeably high at 150 ng/ml. Endomyocardial biopsy from the right ventr icle showed infiltration of eosinophils and dense deposits of ECP in the en docardium as well as the myocardium. Steroid treatment returned the total e osinophil count and serum ECP to normal, with satisfactory improvement in c linical features. Eosinophilia may cause cardiac damage, and this report co nfirms that eosinophil degranulation is toxic. Thus, serum ECP seems to be a reliable indicator for diagnosis and for determining treatment parameters of eosinophilic myocarditis.