title: Electrocardiogram and Chagas disease: a large population database of primary care patients.
abstract: BACKGROUND
  Chagas disease (ChD) used to be a disease restricted to Latin America, but has become a worldwide problem due to migration of infected individuals to developed countries. Electrocardiography has been considered an essential exam to evaluate ChD patients.
  
  
  OBJECTIVE
  This study sought to identify prevalent electrocardiographic abnormalities in a large sample of ChD patients evaluated in the primary care setting.
  
  
  METHODS
  This retrospective observational study assessed all consecutive digital 12-lead electrocardiograms (ECG) performed by the Telehealth Network of Minas Gerais, Brazil, from January 1 to December 31, 2011. In that time, the service attended primary care patients in 660 cities in the Minas Gerais province. ChD was self-reported, and the individuals who did not report having ChD were considered noninfected. The prevalence of electrocardiographic abnormalities was assessed.
  
  
  RESULTS
  Self-reported ChD patients comprised 7,590 (2.9%) of 264,324 patients who underwent ECG during the study period. The mean age for ChD patients was 57.0 ± 13.7 years, and 64.1% of patients were women. The most common comorbidities were hypertension (61.3%), diabetes (9.1%), and dyslipidemia (6.9%), and 10.7% were smokers. The most frequent electrocardiographic abnormalities were nonspecific repolarization abnormalities (34.6%), right bundle branch block (RBBB) (22.7%), left anterior hemiblock (LAH) (22.5%), ventricular premature beats (5.4%), and atrial fibrillation (5.4%). Only 31.5% of the patients had no electrocardiographic abnormality versus 61.2% in noninfected individuals (p < 0.001). The prevalence of normal ECG decreased with aging and was significantly lower than for noninfected individuals in all age groups. Pacemaker rhythm (odds ratio [OR]: 13.3, 95% confidence intervals [CI]: 11.5 to 15.4), RBBB (OR: 10.7, 95% CI: 10.1 to 11.4), especially in association with LAH (OR: 12.1, 95% CI: 11.2 to 13.0), second atrioventricular block (OR: 4.1, 95% CI: 2.5 to 6.6), and third atrioventricular block (OR: 13.3, 95% CI: 11.5 to 15.4) were strongly related to ChD.
  
  
  CONCLUSIONS
  In this large sample of primary care patients with ChD, there was a high prevalence of electrocardiographic abnormalities. Pacemaker rhythm, RBBB, especially in association with LAH, and second and third atrioventricular block were strongly related to ChD.
authors.affiliation: Medical School, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Telehealth Center, University Hospital, Universidade Federal de Minas Gerais, Telehealth Network of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Electronic address: milenamarc@gmail.com.
authors.forename: Milena S
authors.initials: MS
authors.lastname: Marcolino
authors.affiliation: Medical School, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Telehealth Center, University Hospital, Universidade Federal de Minas Gerais, Telehealth Network of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Palhares
authors.affiliation: Medical School, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Telehealth Center, University Hospital, Universidade Federal de Minas Gerais, Telehealth Network of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Lorena R
authors.initials: LR
authors.lastname: Ferreira
authors.affiliation: Medical School, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Telehealth Center, University Hospital, Universidade Federal de Minas Gerais, Telehealth Network of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Ribeiro
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D054537:Atrioventricular Block / Q000453:epidemiology* / Q000503:physiopathology; D001938:Brazil / Q000453:epidemiology; D002037:Bundle-Branch Block / Q000453:epidemiology* / Q000503:physiopathology; D016022:Case-Control Studies; D002598:Chagas Cardiomyopathy / Q000453:epidemiology* / Q000503:physiopathology; D014355:Chagas Disease / Q000453:epidemiology; D016208:Databases, Factual; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D011320:Primary Health Care; D012189:Retrospective Studies