title: Brain natriuretic peptide based strategy to detect left ventricular dysfunction in Chagas disease: a comparison with the conventional approach.
abstract: BACKGROUND
  Left ventricular dysfunction (LVd) is the main predictor of mortality in Chagas disease (ChD).
  
  
  OBJECTIVE
  To compare the diagnostic performance of the conventional approach (ECG and chest X-ray) in the recognition of LVd in ChD, with a new strategy, in which BNP is measured in patients with an abnormal ECG.
  
  
  METHODS
  Consecutive ChD patients recruited at an Outpatient Reference Center in Belo Horizonte, Brazil, without other systemic diseases, in 1998-99 (sample 1, n = 165) and in 2001-02 (sample 2, n = 62) underwent ECG, chest X-ray, BNP measurement and echocardiography.
  
  
  RESULTS
  The prevalence of LVd (ejection fraction <or=0.40) was 9.1% in the sample 1. The conventional strategy recognized all patients with LVd (sensitivity: 100%, 95% CI: 79.6-100% and negative predictive value -PV 100%, 92.1-100%), but with low specificity (30%, 95% CI: 23.2-37.8) and +PV (12.5%, 95% IC: I7.7-19.6). The BNP/ECG strategy showed significantly better specificity (96.0%, 95% CI: 91.5-98.2, p < 0.001) and +PV (66.7%, 95% CI: 43.7-83.7, p < 0.001), and non-significantly lower sensitivity (80.0%, 95% CI: 54.8-93.0, p = 0.25) and -PV (98.0%,95% CI: 94.2-99.3, p = 0.08). Overall accuracy was improved with the new strategy. (94.5%,95% CI: 90.0-97.1 x 36.4%, 95% CI: 29.4-43.9, p < 0.001). Similar results were obtained for the sample 2.
  
  
  CONCLUSIONS
  The BNP-based strategy was more accurate than the conventional approach in the detection of LVd in ChD patients and should be considered as a valid option.
authors: Postgraduate Course of Tropical Medicine, Internal Medicine Department, School of Medicine, Federal University of Minas Gerais, Av. Alfredo Balena, 190-Campus Saúde, 30130-100, Belo Horizonte, Brazil. tom@hc.ufmg.br
authors: Antonio Luiz P
authors: AL
authors: Ribeiro
authors: Mauro M
authors: MM
authors: Teixeira
authors: Adelina M
authors: AM
authors: Reis
authors: Andre
authors: A
authors: Talvani
authors: Amanda A
authors: AA
authors: Perez
authors: Márcio Vinicius L
authors: MV
authors: Barros
authors: Manoel Otávio C
authors: MO
authors: Rocha
mesh_terms: D000328:Adult; D000368:Aged; D014355:Chagas Disease / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology*; D004562:Electrocardiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D020097:Natriuretic Peptide, Brain