title: [The usefulness of the application of nonlinear dynamics in the analysis of electrocardiograms in Chagas' disease patients].
abstract: OBJECTIVE
  The application of nonlinear techniques allows the definition of early risk markers in patients with Chagas infection and without any evidence of cardiac involvement evaluated by standard diagnostic test. Nonlinear modeling techniques have proved to be effective in cardiac rhythm analysis, thereby justifying its use in Chagas' disease.
  
  
  METHODS
  The routine noninvasive test and heart rate variability analysis were performed in Chagas' disease patients and in a group of healthy subjects. In a second phase we used nonlinear analysis in the evaluation of patients with Chagas infection and no evidence of heart disease, Chagasic patients with minimal electrocardiographic abnormalities and healthy controls.
  
  
  RESULTS
  Twenty-four-hour electrocardiographic ambulatory monitoring and heart rate variability allowed us to establish differences between the healthy subjects and patients with Chagas infection without evidence of cardiac disease (p c 0.05 and p <0.005). In sharp contrast nonlinear analysis characterized 4 subgroups in Chagasic patients without cardiac involvement (sensitivity and specificity of 1 00%).
  
  
  CONCLUSIONS
  Our findings suggest that nonlinear modeling techniques have a high sensitivity and specificity in the early detection of cardiac involvement and very early autonomic disturbance. We recommend that these techniques be applied to patients with high risk of cardiac disease other than Chagasic myocarditis. Our findings should be corroborated with studies in larger populations. We are currently developing a prospective study to this end.
authors.affiliation: Laboratorio de Cardiología Experimental. Instituto de Medicina Tropical. Facultad de Medicina. Universidad Central de Venezuela. fmoleiro@reacciun.ve
authors.forename: F
authors.initials: F
authors.lastname: Moleiro
authors.forename: A E
authors.initials: AE
authors.lastname: Rodríguez
authors.forename: F
authors.initials: F
authors.lastname: Misticchio
authors.forename: V
authors.initials: V
authors.lastname: Ruesta
authors.forename: J A
authors.initials: JA
authors.lastname: Octavio
authors.forename: E
authors.initials: E
authors.lastname: Alvarez
authors.forename: A
authors.initials: A
authors.lastname: Fernández
authors.forename: J
authors.initials: J
authors.lastname: Jiménez
authors.forename: A
authors.initials: A
authors.lastname: Marcano
authors.forename: M
authors.initials: M
authors.lastname: Vizcardo
mesh_terms: D000328:Adult; D000465:Algorithms; D016022:Case-Control Studies; D002598:Chagas Cardiomyopathy / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory / Q000592:standards*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D012815:Signal Processing, Computer-Assisted
vernacular_title: Utilidad de la aplicación de técnicas de modelado no lineal en el análisis de electrocardiogramas de pacientes con infección chagásica.