The prognostic significance of electrocardiographic changes in Chagas disease

The meaning of electrocardiographic changes appearing during the clinical follow-up of Chagas disease (ChD) is unknown. In this study, a patient cohort with ChD was followed to describe the electrocardiographic changes that may make it possible to identify patients whose left ventricular function has deteriorated.

The study sample consisted of a prospective cohort followed since 1998 to 1999, involving 220 patients aged 15 to 55 years, 30 controls, and 190 with ChD, without other comorbidities. The group was reexamined between 2004 and 2006, and new electrocardiograms were obtained for 153 patients, 25 (83%) of 30 in the control group and 128 (72%) of 177 in the ChD group. Electrocardiographic variables associated with a significant decrease in ejection fraction (5% or more) were identified.

A significant decrease in ejection fraction was observed in 21 patients in the ChD group (18.7%) but in none of the non-ChD group (P = .024). Only the presence of a new electrocardiographic abnormality and an increase in QRS duration correlated with a decrease in an ejection fraction of 5% or more. QRS duration was correlated with both an increase in left ventricle diastolic diameter and a deterioration in the ejection fraction (r(s) = 0.225, P = .017, and r(s) = -0.300, P < .001). A QRS increase of 5 milliseconds had 77.8% sensitivity and 62.2% specificity for identifying patients with significant decrease in ejection fraction.

The increase in the duration of the QRS complex and the appearance of new electrocardiographic alterations may help in identifying patients with a significant decrease (of 5% or more) in left ventricle ejection fraction.