title: Response to preventive cardiac resynchronization therapy in patients with ischaemic and nonischaemic cardiomyopathy in MADIT-CRT.
abstract: OBJECTIVE
  There are no data regarding the differential response to cardiac resynchronization therapy with defibrillator (CRT-D) by the aetiology of cardiomyopathy in mildly symptomatic patients. We evaluated the outcome of patients enrolled in MADIT-CRT by ischaemic and non-ischaemic aetiology of cardiomyopathy (ICM and non-ICM, respectively).
  
  
  RESULTS
  The clinical response to CRT-D was assessed among ICM (n = 1046) and non-ICM (n = 774) patients enrolled in MADIT-CRT during an average follow-up of 2.4 years, and echocardiographic response was assessed at 1 year. Cardiac resynchronization therapy with defibrillator vs. ICD therapy was associated with respective 34% (P = 0.001) and 44% (P = 0.002) reductions in the risk of heart failure or death among ICM and non-ICM patients (P for interaction = 0.455). In the ICM group, CRT-D was associated with mean (±SD) 29 ± 14% and 18 ± 10% reductions in left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV), respectively. In the non-ICM group, CRT-D was associated with significantly greater volume reductions compared with the ICM group [37 ± 16% and 24 ± 12% reductions in LVESV and LVEDV, respectively (P < 0.001 for all)]. Risk subsets in the ICM group that showed a favourable clinical response to CRT-D included patients with QRS ≥150 ms, systolic blood pressure <115 mmHg, and left bundle branch block (LBBB), whereas in the non-ICM group females, patients with diabetes mellitus, and LBBB, displayed a favourable clinical response.
  
  
  CONCLUSIONS
  Mildly symptomatic ICM and non-ICM patients show significant differences in the echocardiographic response to CRT-D and in the clinical benefit within risk subsets suggesting that risk assessment for CRT-D in this population should be aetiology-specific.
authors.affiliation: Cardiology Division, Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, NY, USA. alon.barsheshet@heart.rochester.edu
authors.forename: Alon
authors.initials: A
authors.lastname: Barsheshet
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.forename: Michael
authors.initials: M
authors.lastname: Eldar
authors.forename: David T
authors.initials: DT
authors.lastname: Huang
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.forename: Helmut U
authors.initials: HU
authors.lastname: Klein
authors.forename: W Jackson
authors.initials: WJ
authors.lastname: Hall
authors.forename: Mary W
authors.initials: MW
authors.lastname: Brown
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Goldberger
authors.forename: Robert E
authors.initials: RE
authors.lastname: Goldstein
authors.forename: Claudio
authors.initials: C
authors.lastname: Schuger
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: James P
authors.initials: JP
authors.lastname: Daubert
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods* / Q000401:mortality; D009202:Cardiomyopathies / Q000150:complications / Q000401:mortality / Q000628:therapy*; D017147:Defibrillators, Implantable; D005260:Female; D006333:Heart Failure / Q000517:prevention & control*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000401:mortality / Q000628:therapy*; D018570:Risk Assessment; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000517:prevention & control