Electrocardiographic changes during and after benznidazole treatment against acute-stage Chagas disease indigenous to the Brazilian Amazon

Abstract

This article aims to assess the cardiac impairment associated with acute infections by Trypanosoma considering abnormalities in electrical conduction and heart rate during the acute phase and after treatment in a case-study of Chagas' disease indigenous to the Amazon. The individuals assessed were grouped into two cohorts: cohort I had patients during the acute phase of the disease; and cohort II included the same patients re-evaluated at the average period of the first cohort, 3.9 years after treatment. The electrocardiographic analysis of the individuals in cohort I was based both on restored electrocardiograms that underwent a new reading and on electrocardiograms performed prospectively. All patients were treated with benznidazole on a regular basis. A total of 179 individuals that had acute Chagas disease in the period between 1992 and 2005 were assessed. During the acute phase, 47.7% of the electrocardiographic tracings were normal, and 52.3% reported abnormalities. The diffuse changes in ventricular repolarization and low QRS voltage were the main abnormalities reported. Cardiac impairment characterized by myopericarditis was observed in 39.1% of the patients, and 24.3% (17/70) of the cases were considered severe. The electrocardiographic changes were more frequent after treatment of patients who had shown electrocardiographic abnormalities during the acute phase, when compared to those who had not. Five other individuals who were diagnosed late and presented with diffuse myocarditis during the acute phase evolved poorly because they developed a clinical picture with lesions of chronic cardiopathy.