[No association between persistence of the parasite and electrocardiographic evolution in treated patients with Chagas disease].

Background: At the present time the assessment of results of treatment of Chagas disease is mainly parasitological. Anti Trypanosoma cruzi IgGs remain positive practically lifelong and electrocardiographic tracings are not usually used as criteria of improvement.

Aim: To determine, in a long term follow up, if electrocardiographic evolution is associated with the persistence of the parasite in treated patients with chronic Chagas disease.

Material And Methods: Thirty patients with chronic Chagas disease that participated in a randomized trial of treatment with itraconazole or allopurinol, were studied. Seven years after treatment, patients were classified in group I if they had a positive xenodiagnosis test, polymerase chain reaction and hybridization in blood or in group II if they had negative tests. A 12 lead electrocardiogram (EKG) was performed each year to all patients.

Results: Seventeen patients were classified in group I and 13 in group II. At baseline 10 patients in group I and 8 in group II had a normal EKG. Six years after treatment 13 patients in group I and 10 in group II had a normal tracing. Of those with a normal tracing at baseline, only one patient in each group presented alterations after six years. A regression of abnormal tracings was observed in four and three patients of groups I and II respectively.

Conclusions: There is no association between the persistence of the parasite in treated patients with Chagas disease and the evolution of electrocardiographic tracings.