title: Sex Differences in Long-Term Outcomes With Cardiac Resynchronization Therapy in Mild Heart Failure Patients With Left Bundle Branch Block.
abstract: BACKGROUND
  Previous studies have shown conflicting results regarding the benefit of cardiac resynchronization therapy (CRT) by sex and QRS duration.
  
  
  RESULTS
  In the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT), we evaluated long-term clinical outcome of heart failure (HF) or death, death, and HF alone by sex and QRS duration (dichotomized at 150 ms) in left bundle-branch block patients with CRT with defibrillator backup (CRT-D) versus implantable cardioverter-defibrillator (ICD) only. There were 394 women (31%) and 887 men with left bundle-branch block. During the median follow-up of 5.6 years, women derived greater clinical benefit from CRT-D compared with implantable cardioverter-defibrillator only, with a significant 71% reduction in HF or death (hazard ratio [HR] 0.29, P<0.001) and a 77% reduction in HF alone (HR 0.23, P<0.001) compared with men, who had a 41% reduction in HF or death (HR 0.59, P<0.001) and a 50% reduction in HF alone (HR 0.50, P<0.001) (all sex-by-treatment interaction P<0.05). Men and women had similar reduction in long-term mortality with CRT-D versus implantable cardioverter-defibrillator only (men: HR 0.70, P=0.03; women: HR 0.59, P=0.04). The incremental benefit of CRT-D in women for HF or death and HF alone was consistent with QRS <150 or >150 ms.
  
  
  CONCLUSIONS
  During long-term follow-up of mild HF patients with left ventricular dysfunction and wide QRS, both women and men with left bundle-branch block derived sustained benefit from CRT-D versus implantable cardioverter-defibrillator only, with significant reduction in HF or death, HF alone, and all-cause mortality regardless of QRS duration. There is an incremental benefit with CRT-D in women for the end points of HF or death and HF alone.
  
  
  BACKGROUND
  URL: https://clinicaltrials.gov/. Unique identifiers: NCT00180271, NCT01294449, and NCT02060110.
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Yitschak
authors.initials: Y
authors.lastname: Biton
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Helmut
authors.initials: H
authors.lastname: Klein
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Bronislava
authors.initials: B
authors.lastname: Polonsky
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.affiliation: Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D058409:Cardiac Resynchronization Therapy Devices; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation; D005260:Female; D054624:Health Status Disparities; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D020127:Recovery of Function; D012042:Registries; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left
keywords: QRS duration; cardiac resynchronization therapy with defibrillator; clinical outcomes; implantable cardioverter‐defibrillator; long‐term survival; mild heart failure; mortality; sex