Systematic mapping of hearts from chronic chagasic patients: the association between the occurrence of histopathological lesions and Trypanosoma cruzi antigens.

To investigate the role played by Trypanosoma cruzi in the pathogenesis of chronic chagasic cardiopathy, the myocardiums of 12 hearts from individuals who had this condition were mapped in detail. Attempts were made to associate the histopathological lesions observed with the presence of parasitic antigens in the affected tissue. Samples from 26 regions of each heart were submitted to histological analysis and immunostained for the presence of T. cruzi. All cases showed at least one positive region for antigens, but the quantity of antigen detected varied greatly. The regions showing the greatest pathological changes were the inferior atrial septum, the basal and apical portions of the ventricular septum, and the posterior basal and lateral pre-apical regions of the left ventricle. The posterior wall of the right atrium and the posterior basal wall of the left ventricle presented the greatest intensities of inflammation. Fibrosis was intense in the right atrium, the posterior basal and pre-apical left ventricular free walls and the apex. The regions in which T. cruzi antigens were detected showed the most intense inflammation. However, as there was no significant correlation between the intensity of the lesions and the quantity of parasitic antigen, other mechanisms, such as auto-immunity or hypersensitivity, may stimulate the inflammation.