title: New strict left bundle branch block criteria reflect left ventricular activation differences.
abstract: OBJECTIVE
  Pacing lead electrical delays and strict left bundle branch block (LBBB) criteria were assessed against cardiac resynchronization therapy (CRT) outcome.
  
  
  METHODS
  Forty-nine patients with LBBB and QRS duration >130 milliseconds underwent CRT-implantation. Sensed right ventricular to left ventricular electrical delay (RV-LV-IED) was measured. Response to CRT was defined as ≥15% decrease in left ventricular end-systolic volume.
  
  
  RESULTS
  Eighteen of 20 (90%) patients with non-ischemic dilated cardiomyopathy (DCM) and 18 of 29 (62%) with ischemic heart disease (IHD) responded to CRT, p<0.01. When applying new strict ECG criteria subsequent rates of response in DCM were 18/19 (95%) and in IHD of 18/23 (78%) respectively, p<0.05 between IHD groups. Correspondingly, RV-LV-IED was longer in DCM compared to IHD patients and in responders compared to non-responders, p=0.017 and p<0.001, respectively.
  
  
  CONCLUSIONS
  Interventricular electrical delay predicts left ventricular remodeling after CRT and new, strict ECG criteria of LBBB are superior in predicting remodeling.
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Hobrovej 16-18, 9000 Aalborg, Denmark. Electronic address: kjge@rn.dk.
authors.forename: Kasper
authors.initials: K
authors.lastname: Emerek
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Risum
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Hobrovej 16-18, 9000 Aalborg, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Hjortshøj
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Hobrovej 16-18, 9000 Aalborg, Denmark.
authors.forename: Sam
authors.initials: S
authors.lastname: Riahi
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Hobrovej 16-18, 9000 Aalborg, Denmark.
authors.forename: Jeppe Grøndahl
authors.initials: JG
authors.lastname: Rasmussen
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Hobrovej 16-18, 9000 Aalborg, Denmark.
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Bloch Thomsen
authors.affiliation: Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7D2, 9220 Aalborg, Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Graff
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Hobrovej 16-18, 9000 Aalborg, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Søgaard
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000517:prevention & control*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000517:prevention & control*
keywords: Cardiac resynchronization therapy; Heart failure; Interventricular electrical delay; Ischemic heart disease; Left bundle branch block; Non-ischemic dilated cardiomyopathy