The use of radioisotope techniques in evaluating and monitoring the degree of cardiac compromise in Chagas' disease patients

The purpose of this work was to evaluate the cardiac effect of Chagas' disease by means of myocardial scintigraphy with thallium-201 and radioisotopic ventriculograms with 99Tcm-labelled red blood cells in equilibrium, evaluating the presence or absence of alterations in myocardial perfusion and in left ventricular function in Chagas' disease patients of groups I, II and III. The first two groups were monitored after a period of 4 to 5 years for the purpose of checking on the development of myocardial damage and its intensity during this period. A study was made of 26 patients (19 men) (average age: 47 ± 10 years); of these, 8 belonged to group I (age: 45 ± 10), 10 to group II (age: 49 ± 7) and 8 to group III (age 46 ± 7). Thallium-201 was administered to all the patients of groups I and II during effort and redistribution and radioisotopic ventriculograms were made during rest and exercise. The same method of evaluation was repeated after a period of 4 to 5 years. The patients of group III were evaluated only during rest, in view of the difficulties of analysing the radioisotopic ventriculograms due to their arrhythmias. Myocardial perfusion is compromised in 60% of the Chagas' disease patients in group I and in all the patients of groups II and III. The following shows a progressive regionalization of these alterations in the group II patients. Ventricular function during rest was normal in the patients of groups I and II, and abnormal in those of group III (p < 0.01, p < 0.05, respectively). Ventricular function during effort in the group I patients shows a significant decrease during the follow-up period (p < 0.05). Emphasis should be placed on the sensitivity of radioisotope techniques for detecting myocardial damage in the preclinical stage (without cardiomegaly) of this disease. (author). 31 refs, 6 figs, 3 tabs