title: Cardiac resynchronisation therapy is not associated with a reduction in mortality or heart failure hospitalisation in patients with non-left bundle branch block QRS morphology: meta-analysis of randomised controlled trials.
abstract: OBJECTIVE
  Recently published clinical guidelines recommend cardiac resynchronisation therapy (CRT) for patients with heart failure (HF) with reduced LVEF and non-left bundle branch block (non-LBBB) QRS morphology. We sought to define the potential benefit of CRT in these patients through meta-analysis of randomised controlled trials (RCTs) that have reported outcomes in patients with non-LBBB QRS morphology.
  
  
  METHODS
  We searched MEDLINE and EMBASE for RCTs of CRT that reported outcomes according to QRS morphology. We performed meta-analysis of these RCTs to assess the effect of CRT on the end points of death, HF hospitalisation, and the composite of death and HF hospitalisation.
  
  
  RESULTS
  Five RCTs were analysed, including 6523 participants (1766 with non-LBBB QRS morphology). CRT was not associated with a reduction in death and/or HF hospitalisation in subjects with non-LBBB QRS morphology (HR 0.99 95% CI 0.82 to 1.20).
  
  
  CONCLUSIONS
  CRT is not associated with a reduction in death or HF hospitalisation in patients with non-LBBB QRS morphology. Wide QRS with non-LBBB morphology remains an area of uncertainty for CRT, which is included in the recent European Society of Cardiology guidelines with a weaker strength of recommendation, but is not supported by a dedicated RCT.
authors: Manchester Heart Centre, Manchester Royal Infirmary, Manchester, UK.
authors: Colin
authors: C
authors: Cunnington
authors: Cardiovascular Institute, University of Manchester, Manchester, UK.
authors: Chun Shing
authors: CS
authors: Kwok
authors: Department of Cardiology, University Hospital of North Staffordshire, Stoke-on-Trent, UK.
authors: Duwarakan K
authors: DK
authors: Satchithananda
authors: Department of Cardiology, University Hospital of North Staffordshire, Stoke-on-Trent, UK.
authors: Ashish
authors: A
authors: Patwala
authors: Manchester Heart Centre, Manchester Royal Infirmary, Manchester, UK.
authors: Muhammad A
authors: MA
authors: Khan
authors: Manchester Heart Centre, Manchester Royal Infirmary, Manchester, UK.
authors: Amir
authors: A
authors: Zaidi
authors: Manchester Heart Centre, Manchester Royal Infirmary, Manchester, UK Cardiovascular Institute, University of Manchester, Manchester, UK.
authors: Fozia Z
authors: FZ
authors: Ahmed
authors: Manchester Heart Centre, Manchester Royal Infirmary, Manchester, UK Cardiovascular Institute, University of Manchester, Manchester, UK Farr Institute, University of Manchester, Manchester, UK.
authors: Mamas A
authors: MA
authors: Mamas
mesh_terms: D002037:Bundle-Branch Block / Q000503:physiopathology; D058406:Cardiac Resynchronization Therapy / Q000401:mortality*; D004562:Electrocardiography; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016019:Survival Analysis; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology