Histopathology of specialized and ordinary myocardium and nerves in chronic Chagas disease, with a morphometric study of inflammation and fibrosis.

Chagas disease, in the chronic phase, is known to be characterized by cardiac failure, and/or arrhythmias. To assess the involvement of the conduction system and of the working myocardium, morphometric and immunohistochemistry studies have been carried out on 4 autoptic hearts of chronic chagasic myocardiopathy. The characterization of interstitial infiltrates was performed by lymphocyte immunophenotyping with immunocytochemical techniques. These infiltrates were more prominent in the working myocardium and in the left branch of the His bundle. The infiltrates consisted of about 50% of macrophages and 50% of T-lymphocytes. Mast cells would not play a role in the chronic stages of the disease. Eosinophils were present in no more than the 5% of the inflammation. The fibrosis, especially of the conducting system seems to be facilitated by an impaired lymphatic outflow, whereas the evidence of neuroganglionic involvement was variable.