Cardiac form of American Trypanosomiasis 



by 

 CARLOS CHAGAS and EURICO VILLELA 



In the clinical picture of American Tryp- 

 anosomiasis there are certain very constant 

 and prominent symptoms which characterize 

 the cardiac form of the disease. To give them 

 firm foundation in fact and to avert the 

 possibility of objections, our studies abound 

 in decisive results derived from animal exper- 

 imentation and human autopsies in which 

 the constancy of the histopathologic proc- 

 esses and the presence of the parasites in 

 the myocardium justify the interpretation of 

 the principal features of the cardiac form. 



In the clinical picture of this disease 

 the lesions found in the cardiac muscle cer- 

 tainly represent the predominating factor; 

 however, in a suiveyof the symptoms based 

 on a large number of observed cases it is 

 fitting to systematize the facts in two groups, 

 one consisting of the cardiac changes of 

 muscular origin and the other of changes 

 associated witn deficient nervous influences. 

 These latter, which are attributable to the 

 general pathologic processes of the disease, 

 sometimes occur alone but usually are as- 

 sociated with changes of the former order. 

 Here alterations of the cardiac rhythm oc- 

 cupy the chief place in the physical find- 

 ings. Arrhythmia constitutes the predomi- 



nant note in such cardiopathies, and in its 

 various types are interpreted anomalies of 

 the principal functions of the muscle. Fur- 

 thermore, these types almost always succeed 

 one another or complicate one another in 

 the same individual. And this is not to be 

 wondered at when one recognizes the pro- 

 gressive intensity and the diffusion of the 

 pathologic process throughout the whole 

 myocardium with its possible localizations 

 in specialized functional zones of the organ. 

 For facility of description we must 

 study the cardiac changes in the disease 

 with the nature of the predominant arrhy- 

 thmia. The functional changes of a general 

 order, which give better ground for prog- 

 nosis and so ought to form the criterion for 

 a clinical classification, do not show appre- 

 ciable variations but rather a relative uni- 

 formity in the different patients, and this 

 prevents them serving for the basis of sharp- 

 ly delimited pathologic groups. Under these 

 conditions we will study the following 

 groups of alteration of rhythm: 



1. Total tachycardias and bradycardias 

 (of sinus origin) 



2. Alterations of conductibility, mani- 

 fested by 



