12 



of the phases of the arrhythmia, in the ear- 

 liest as well as in complete block. And here, 

 with the great number of cases that we have, 

 we cannot confirm th greater intensity of 

 such symptoms in the phases that precede 

 the establishment of the idio-ventricular 

 rhythm. Vertigo, syncopal attacks and con- 

 vulsions have been seen in patients with part- 

 ial and total block, perhaps in a little larger 

 number of the first but in all stages of the 

 arrhythmia. 



At this point it should be noted that 

 the number of ventricular beats in cases of 

 complete block undergoes frequent varia- 

 tions, which are doubtless related to the al- 

 terations in excitability of the muscle. From 

 forty pulsations to the minute, and some- 

 times more, the rate of the idio-ventricular 

 rhythm passes to thirty or even less, and 

 this may explain the frequency of nervous 

 symptoms in cases of this kind. 



Other symptoms could be given here if 

 we wished to glean them from the great 

 number of observations of the cardiac form 

 that we have. We prefer, however, to at once 

 treat of other subjects. 



Course. 



As regards the clinical course of the 

 cardiac form we must state that this is the 

 type of the disease that occasions the 

 greatest mortality. 



The death rate in the cardiac form is 

 relatively very high; in spite of this, a large 

 number of cases remain in a state of toler- 

 ance for many years, capable of carrying 

 on their work, although the insufficiency of 

 the heart is more or less marked. Accord- 

 ing to our observations, this can be found 

 in nearly all forms of arrhytlimia except 

 those of flutter and auricular fibrillation, 

 the prognosis of which we consider very 

 grave and we do not believe that thev 

 can long survive. In a general way we can 

 state that the course of the cardiac affection 

 in this disease is progressive. Here there is 

 no possibility of regression and the patients 

 proceed more or less rapidly to a lethal ter- 

 mination. 



Death from the disease. 



SUDDEN DEATH 



Sudden death is extremely frequent in 

 the regions of endemic trypanosomiasis. We 

 have had the opportunity of seeing it in 

 several cases of the cardiac form at the 

 place where we were carrying on our work 

 and its frequence is made more impressive 

 by the unanimous reports of the inhabitants 

 of such regions where a large number of 

 the families mourn the sudden death of one 

 or of various members. The individuals fre- 

 quently die in the fulness of their youth and 

 in an apparent healthy condition during the 

 phase of tolerance of the cardiac affection. 

 Many of them die while engaged in their 

 usual work without any immediate cause to 

 explain the occurrence; but others die at 

 the moment of an extra exertion, or of fa- 

 tigue, or of some other accident that is ca- 

 pable of exhausting the deficient energy of 

 the myocardium. Facts of this kind are nu- 

 merous and plainly show the intensity of 

 the pathologic processes of the disease. We 

 do not know of another condition in human 

 pathology that causes sudden death in so 

 high a proportion of cases as does Amer- 

 ican trypanosomiasis. 



What is the exact mechanism of this 

 death? Can we determine it with certain- 

 ty in a way to cover all of the facts? And 

 will it be the same for all of the occurrences 

 of this order? In the explanation of this 

 mechanism we must note in the first place 

 that sudden death is observed in any of the 

 forms of arrhythmia, which in a way ren- 

 ders its exact interpretation difficult. On the 

 other hand we must remember that usually 

 the patients show different forms of arrhy- 

 thmia simultaneouslv and that cases are rare 

 that have one form of rhythm exclusively. 

 And if this is so, the unity of that mechan- 

 ism must be admitted once there is recog- 

 nized the occurrence of the fact in one of 

 the most frequent arrhythmias. Now, of 

 these, arrhythmia by extrasystole is doubt- 

 less that which is repeated in the greatest 

 number of patients associated with other 



