Early clinics of the cardiac forms of Chagas' disease: Discovery and study of original medical files (1909-1915)

We have uncovered 80 medical files corresponding to original cases of Chagas' disease used for the classical description of the acute and cardiac forms of the disease. Sixty of them were diagnosed cardiac forms of the disease. The detailed clinical description of these 60 files is in excellent agreement with the nosography of progressive heart disease given by Chagas in his original 1922 paper. The reports we had access to, characterize a novel form of cardiac disease, dominated by progressive AV block, enlargement and displacement of the heart and sudden death, in relatively young adults including juveniles. In contrast to that remarkable clinical description, the assertion made by Chagas that this set of clinical signs was the consequence of an earlier infection by Trypanosoma cruzi rests on weak evidence, due to the difficulty to identify the parasite in most patients. Moreover, the association of thyroid dysfunction with cardiac disease emphasized by Chagas cannot be deduced from the files we have examined. Finally, the main reason why the disease had not been recognized for long as a defined clinical entity, is likely the absence of markedly distinctive clinical signs compared to most other parasitic diseases, poor sanitary conditions and the probable lack of clinical skills of the rare doctors working in the area where the disease was described.