title: Iodine-123 metaiodobenzylguanidine cardiac imaging as a method to detect early sympathetic neuronal dysfunction in chagasic patients with normal or borderline electrocardiogram and preserved ventricular function.
abstract: OBJECTIVE
  The indeterminate form of Chagas disease represents the most common chronic presentation. The aim of this study was to assess cardiovascular autonomic system function with I-123 metaiodobenzylguanidine (MIBG) scintigraphy in chagasic patients with normal or "borderline" electrocardiographic alterations and preserved left ventricular function evaluated by echocardiography.
  
  
  METHODS
  A total of 40 chagasic patients and 19 control subjects were included in this study. Patients had normal echocardiogram and chest radiography; no arrhythmias or myocardial ischemia; and normal exercise performance for age, gender, and body mass index. I-123 MIBG scintigraphy was performed and the heart-to-mediastinum (H/M) uptake was used as the primary predictor in the present analysis. The data analysis was performed by using Nonparametric Regression Trees and the Survival Agreement Plot. We included only patients with preserved right and left ventricular function assessed by echocardiographic methods.
  
  
  RESULTS
  Variables analyzed in the regression tree were age, sex, 20 minutes and 3 hours H/M uptake after injection of I-123 MIBG, washout rate, and single photon emission computed tomography imaging. The 3 hours H/M ratio was the only significant variable (P<0.001) and for 95% of chagasic patients, this value was less than 2.19.
  
  
  CONCLUSIONS
  This study presents evidence that cardiac autonomic sympathetic modulation may be affected in chagasic subjects with preserved ventricular function evaluated by echocardiography, especially in those with "borderline" electrocardiogram.
authors.affiliation: Department of Radiology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Maria Carolina P
authors.initials: MC
authors.lastname: Landesmann
authors.forename: Lea Mirian Barbosa
authors.initials: LM
authors.lastname: da Fonseca
authors.forename: Basilio
authors.initials: B
authors.lastname: de B Pereira
authors.forename: Emília M
authors.initials: EM
authors.lastname: do Nascimento
authors.forename: Paulo Henrique
authors.initials: PH
authors.lastname: Rosado-de-Castro
authors.forename: Sergio Augusto Lopes
authors.initials: SA
authors.lastname: de Souza
authors.forename: Ronaldo
authors.initials: R
authors.lastname: de S L Lima
authors.forename: Roberto C
authors.initials: RC
authors.lastname: Pedrosa
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D000368:Aged; D057791:Cardiac Imaging Techniques / Q000379:methods*; D014355:Chagas Disease / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015899:Tomography, Emission-Computed, Single-Photon; D014463:Ultrasonography; D016276:Ventricular Function / Q000502:physiology*
chemical_list: D019797:3-Iodobenzylguanidine