title: Relationship between fibrosis and ventricular arrhythmias in Chagas heart disease without ventricular dysfunction.
abstract: BACKGROUND
  Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis.
  
  
  OBJECTIVE
  To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia.
  
  
  METHODS
  Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram.
  
  
  RESULTS
  The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001).
  
  
  CONCLUSIONS
  Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups.
authors.affiliation: Instituto de Cardiologia Edson Saad, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
authors.forename: Eduardo Marinho
authors.initials: EM
authors.lastname: Tassi
authors.affiliation: Hospital Frei Galvão, Guaratinguetá, SP, Brasil.
authors.forename: Marcelo Abramoff
authors.initials: MA
authors.lastname: Continentino
authors.affiliation: Instituto de Cardiologia Edson Saad, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
authors.forename: Emília Matos do
authors.initials: EM
authors.lastname: Nascimento
authors.affiliation: Instituto de Cardiologia Edson Saad, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
authors.forename: Basílio de Bragança
authors.initials: Bde B
authors.lastname: Pereira
authors.affiliation: Instituto de Cardiologia Edson Saad, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
authors.forename: Roberto Coury
authors.initials: RC
authors.lastname: Pedrosa
mesh_terms: D000368:Aged; D015992:Body Mass Index; D014355:Chagas Disease / Q000473:pathology / Q000503:physiopathology*; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D005355:Fibrosis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012016:Reference Values; D018709:Statistics, Nonparametric; D013318:Stroke Volume / Q000502:physiology*; D017180:Tachycardia, Ventricular / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology*