title: Electrophysiological characteristics of Chagas disease.
abstract: OBJECTIVE
  Chagas disease has become a global problem due to changing migration patterns. An electrophysiological study is generally indicated for assessing sinus node function, conduction through the atrioventricular node and His-Purkinje system, in addition to evaluating the mechanisms of arrhythmia. The aim of this study was to describe the characteristics of electrophysiological study findings in patients with Chagas disease.
  
  
  METHODS
  A retrospective descriptive study of 115 consecutive patients with Chagas disease undergoing an electrophysiological study over the last three years in a tertiary hospital in Brazil. Baseline characteristics, electrocardiogram, echocardiogram, and 24-hour Holter monitoring findings were recorded and correlated with the electrophysiological study findings.
  
  
  RESULTS
  The corrected sinus node recovery time and sinoatrial conduction time were abnormal in 6.9% and 26.1% of patients, respectively. Thirty-seven (32.2%) had abnormal atrioventricular conduction. Intraventricular conduction was abnormal in 39 (33.9%). Approximately 48% had induced sustained ventricular arrhythmias, most of which were monomorphic (83.6%). Right bundle branch block was the most common morphology (52.7%). Fifty-one percent were associated with symptoms/hemodynamic instability, 60% required electrical cardioversion, and 27.3% needed overdrive suppression. The most common site of origin was the left ventricular inferoseptal wall (18.2%), followed by the left ventricular posterobasal wall (11%). Patients with an ejection fraction<40% had a 1.94-fold increased risk of ventricular arrhythmias compared to those with an ejection fraction>60% (OR: 1.94; 95%CI: 1.12-3.38; p=0.01). The presence of complex ventricular arrhythmias on Holter did not predict inducible ventricular arrhythmias.
  
  
  CONCLUSIONS
  Chagas patients with a low ejection fraction have an increased risk of inducible ventricular arrhythmias. Sinus node dysfunction, and atrioventricular node and His-Purkinje conduction abnormalities occur in about one-third of patients. Complex ventricular arrhythmias on Holter were not associated with an increased risk of inducible ventricular arrhythmias.
authors.forename: Swellen Schuenemann
authors.initials: SS
authors.lastname: Cedraz
authors.forename: Paulo Christo Coutinho da
authors.initials: PC
authors.lastname: Silva
authors.forename: Ricardo Katsumi Yendo
authors.initials: RK
authors.lastname: Minowa
authors.forename: Juliano Furtado de
authors.initials: JF
authors.lastname: Aragão
authors.forename: Danilo Victor
authors.initials: DV
authors.lastname: Silva
authors.forename: Carlos
authors.initials: C
authors.lastname: Morillo
authors.forename: Dalmo Antonio Ribeiro
authors.initials: DA
authors.lastname: Moreira
authors.forename: Ricardo Garbe
authors.initials: RG
authors.lastname: Habib
authors.forename: Bruno Pereira
authors.initials: BP
authors.lastname: Valdigem
authors.forename: Luciana Vidal
authors.initials: LV
authors.lastname: Armaganijan
mesh_terms: D014355:Chagas Disease / Q000503:physiopathology*; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies