title: Is conventional cardiac pacing harmful in patients with normal ventricular function?
abstract: BACKGROUND
  Right ventricular pacing may be deleterious in patients with left ventricular dysfunction, but in patients with normal function the impact of this stimulation triggering clinically relevant ventricular dysfunction is not fully established.
  
  
  OBJECTIVE
  To evaluate the clinical, echocardiographic findings of patients with previously normal left ventricular function underwent implantation of a pacemaker.
  
  
  METHODS
  Observational, cross-sectional study with 20 patients, who underwent implantation of pacemaker, prospectively followed-up, with the following inclusion criteria: normal left ventricular function defined by echocardiography and ventricular pacing higher than 90%. Were evaluated functional class (FC) (New York Heart Association), 6-minute walk test (6MWT), B-type natriuretic peptide (BNP), echocardiographic assessment (conventional and dyssynchrony parameters), and quality of life questionnaire (QLQ) (SF-36). The assessment was performed at ten days (t1), four months (t2), eight months (t3), 12 months (t4) and 24 months (t5).
  
  
  RESULTS
  Conventional echocardiographic parameters and dyssynchrony parameters showed statistically significant variation over time. The 6MWT, FC, and BNP showed worsening at the end of two years. QLQ showed initial improvement and worsening at the end of two years.
  
  
  CONCLUSIONS
  The implantation of conventional pacemaker was associated with worsening in functional class, worsening in walk test, increased BNP levels, increased duration of QRS, and worsening in some domains of the QLQ at the end of two years. There were no changes in echocardiography measurements (conventional and asynchrony measures).
authors.forename: Luiz Antonio Batista de
authors.initials: LA
authors.lastname: Sá
authors.forename: Salvador
authors.initials: S
authors.lastname: Rassi
authors.forename: Márcia Andery Ludovico
authors.initials: MA
authors.lastname: Batista
mesh_terms: D000328:Adult; D000368:Aged; D054537:Atrioventricular Block / Q000601:surgery; D001283:Atrioventricular Node / Q000601:surgery; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects* / Q000379:methods; D014355:Chagas Disease / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000503:physiopathology / Q000601:surgery*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000601:surgery*; D016276:Ventricular Function / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology