title: Long-term outcome with cardiac resynchronization therapy in mild heart failure patients with left bundle branch block from US and Europe MADIT-CRT.
abstract: Early intervention with cardiac resynchronization therapy with defibrillator (CRT-D) in mild heart failure (HF) patients with a left bundle branch block (LBBB) ECG pattern was associated with a significant reduction in mortality in the long-term MADIT-CRT trial. Whether patients in MADIT-CRT enrolled from centers in the USA and in Europe have different long-term clinical response to CRT-D remains unknown. We compared the baseline clinical characteristics and clinical and echocardiographic long-term clinical response to CRT-D between MADIT-CRT patients with LBBB who were enrolled in USA (n = 871) and European centers (n = 392). Although European patients had more advanced heart disease than US patients, CRT-D was associated with similar 60 % (p < 0.001) reductions in the risk of HF in US and European patients when compared to ICD-only therapy after adjustment for relevant baseline clinical covariates. US patients had significant long-term mortality reduction (38 %, p = 0.02) while among European patients the survival benefit associated with CRT-D was not statistically significant (HR 0.73, p = 0.18); subgroup analyses revealed a significantly greater CRT-D benefit among women who were enrolled in the USA, whereas no significant gender difference in the clinical benefit of CRT-D was observed in the European cohort. Reverse remodeling at 1 year was associated with significantly better clinical outcomes in both groups. Despite differences in baseline disease severity, European and US patients with LBBB experienced a similar clinical and echocardiographic response to cardiac resynchronization therapy during long-term follow-up.
  
  
  BACKGROUND
  http://clinicaltrials.gov/ct2/show/NCT00180271 .
authors.affiliation: Heart Research Follow-Up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, 265 Crittenden Blvd., PO Box 653, Rochester, NY, 14642, USA, yitschak.biton@heart.rochester.edu.
authors.forename: Yitschak
authors.initials: Y
authors.lastname: Biton
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: Helmut U
authors.initials: HU
authors.lastname: Klein
authors.forename: Scott D
authors.initials: SD
authors.lastname: Solomon
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.forename: Bronislava
authors.initials: B
authors.lastname: Polonsky
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000209:etiology; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D017147:Defibrillators, Implantable; D004452:Echocardiography / Q000379:methods; D004562:Electrocardiography / Q000379:methods; D005060:Europe / Q000453:epidemiology; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D000069451:Long Term Adverse Effects; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013318:Stroke Volume; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology