[Dilated cardiomyopathy in patients with chronic chagasic infection: report of two fatal autochthonous cases from Rio Negro, State of Amazonas, Brazil].

Two fatal cases of human chronic chagasic cardiomyopathy are reported, for the first time, in autochthonous patients from Rio Negro, Amazonas state. Both cases, (45 year old man and 44 year old woman) who were born and lived their whole lives in the Rio Negro region, in the northern part of the state of Amazonas, reported having been bitten several times by triatomine bugs in their camping huts while gathering pia ava fibers. The patients, who had confirmed positive serology for Trypanosoma cruzi antibodies (indirect immunofluorescence, ELISA and Western blot), developed in the last 5-7 years a progressive cardiac failure, with global enlargement of the heart, atrioventricular and left bundle branch block, ventricular extrasystoles, both dying from irreversible cardiac insufficiency. The histopathology of a post-mortem surgical cardiac biopsy performed in one of the cases showed chronic myocarditis with diffuse mononuclear cell infiltrates, with areas of focal cell accumulation, fibrosis, lytic necrosis of myocardial fibers, suggestive of chronic chagasic myocarditis. An in situ PCR was positive for Trypanosoma cruzi.