ABSTRACT
In 1977 the authors launched a long-term investigation of the epidemiology of Chagas'disease and its cardiac implications in Chile. During this work, clinical examinations were performed, blood samples were drawn for serologic tests, and electrocardiograms were obtained using a study population of 2 938 subjects residing in rural settlements of northern Chile; and this was done again four years later with 481 study subjects remaining in the area. This article reports on the latter four-year followup study. To begin with, the study subjects were divided into three specific groups: those with no evidence of Chagas'disease but with cardiopathy (as indicated by abnormal ECGs) were disignated Group A; those with positive chagasic serology and cardiopathy were designated Group B; and 67 subjects randomly selected from those with positive chagasic serology and normal ECGs were designated Group C. At the time of the followup work, 216 subjects were retained in Group A and 198 in Group B. Comparison of the initial and final Group A and Grup B data yielded a number of results that seem significant. To beigin with, they indicated that mortality was four times higher among the infected subjects and that the disease tended to threaten a much younger population than was threatened by nonchagasic cardiopathy. Also, cardiopathy appeared to develop among the infected Group C subjects at a rate of about 9.7
