title: The prognostic significance of electrocardiographic changes in Chagas disease.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Serviço de Cardiologia e Cirurgia Cardiovascular, Hospital das Clínicas da Universidade Federal de Minas Gerais, 30130-100, Belo Horizonte, Brazil.
authors.forename: Bruno Ramos
authors.initials: BR
authors.lastname: Nascimento
authors.forename: Christiano Gonçalves
authors.initials: CG
authors.lastname: Araújo
authors.forename: Manoel Otávio Costa
authors.initials: MO
authors.lastname: Rocha
authors.forename: José Darlan Pinheiro
authors.initials: JD
authors.lastname: Domingues
authors.forename: Aline Braga
authors.initials: AB
authors.lastname: Rodrigues
authors.forename: Márcio Vinicius Lins
authors.initials: MV
authors.lastname: Barros
authors.forename: Antonio Luiz Pinho
authors.initials: AL
authors.lastname: Ribeiro
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D014355:Chagas Disease / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*