title: Native Electrocardiographic QRS Duration after Cardiac Resynchronization Therapy: The Impact on Clinical Outcomes and Prognosis.
abstract: BACKGROUND
  We investigated whether reversed electrical remodeling (RER), defined as narrowing of the native electrocardiographic QRS duration after cardiac resynchronization therapy (CRT), might predict prognosis and improvement in echocardiographic outcomes.
  
  
  RESULTS
  A total of 110 CRT recipients were retrospectively analyzed for the end points of death and hospitalization during 18 ± 3 months. Native QRS durations were recorded at baseline and 6 months after CRT (when pacing was switched off to obtain an electrocardiogram) to determine RER. CRT response and mitral regurgitation (MR) improvement were defined as ≥15% reduction in left ventricular end-systolic volume and absolute reduction in regurgitant volume (RegV) at 6 months, respectively. Overall, 48 patients (44%) had RER, which was associated with functional improvement (77% vs 34%; P < .001) and CRT response (81% vs 52%; P < .001) compared with those without RER. The change in the intrinsic QRS duration correlated with the reduction in RegV (r = 0.51; P < .001) and in tenting area (r = 0.34; P < .001). RER was a predictor of MR improvement (P = .023), survival (P = .043), and event-free survival (P = .028) according to multivariate analyses.
  
  
  CONCLUSIONS
  Narrowing of the intrinsic QRS duration is associated with functional and echocardiographic CRT response, reduction in MR, and favorable prognosis after CRT.
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey. Electronic address: oguzkaraca@hotmail.com.
authors.forename: Oguz
authors.initials: O
authors.lastname: Karaca
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Beytullah
authors.initials: B
authors.lastname: Cakal
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Mehmet Onur
authors.initials: MO
authors.lastname: Omaygenc
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Haci Murat
authors.initials: HM
authors.lastname: Gunes
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Sinem Deniz
authors.initials: SD
authors.lastname: Cakal
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Kizilirmak
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Tayyar
authors.initials: T
authors.lastname: Gokdeniz
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Irfan
authors.initials: I
authors.lastname: Barutcu
authors.affiliation: Department of Cardiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Bilal
authors.initials: B
authors.lastname: Boztosun
authors.affiliation: Department of Cardiac Electrophysiology, Medipol University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Fethi
authors.initials: F
authors.lastname: Kilicaslan
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D058406:Cardiac Resynchronization Therapy / Q000379:methods* / Q000401:mortality; D002423:Cause of Death; D015331:Cohort Studies; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D054143:Heart Failure, Systolic / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology
keywords: Native QRS duration; cardiac resynchronization therapy response; mitral regurgitation; prognosis; reversed electrical remodeling