title: Effect of cardiac resynchronization therapy on ventricular repolarization: a meta-analysis.
abstract: OBJECTIVE
  Cardiac resynchronization therapy (CRT) was thought to have a proarrhythmic effect on ventricular repolarization. But the results of previous studies were inconsistent. The aim of this study was to determine the effect of CRT on ventricular repolarization.
  
  
  METHODS
  A meta-analysis of studies focused on the effect of CRT on ventricular repolarization in patients undergoing CRT was conducted. Endpoints including QT interval (QT), JT interval (JT), QT dispersion(QTD) and interval between the peak to end of T wave (Tp-e).
  
  
  RESULTS
  A total of 14 studies were included in our meta-analysis. After pooling the data, no significant difference was observed in QT, JT and Tp-e between biventricular (BV) pacing and intrinsic ventricular rhythm. BV paced QTD was lower than intrinsic QTD, but the significance was ambiguous [mean difference (MD): -17.33, 95% CI -34.44 to -0.22, p=0.05]. Left ventricular (LV) paced Tp-e was significantly longer than intrinsic Tp-e (MD: 21.44, 95% CI 2.37 to 40.51, p=0.03). No significant difference was observed in QT, JT and QTD between LV pacing and intrinsic ventricular rhythm.
  
  
  CONCLUSIONS
  In patients undergoing CRT, BV pacing has no deteriorating effect on ventricular repolarization, but LV pacing has a prolonging effect on Tp-e.
authors.affiliation: Department of Cardiology, The First People's Hospital of Hangzhou; Hangzhou-China. duanxu410@yahoo.com.cn.
authors.forename: Xu
authors.initials: X
authors.lastname: Duan
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
mesh_terms: D058406:Cardiac Resynchronization Therapy; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans