title: Functional response to cardiac resynchronization therapy is associated with improved clinical outcome and absence of appropriate shocks.
abstract: BACKGROUND
  We evaluated clinical outcome and incidence of (in)appropriate shocks in consecutive chronic heart failure (CHF) patients treated with CRT with a defibrillator (CRT-D) according to functional response status. Furthermore, we investigated which factors predict such functional response.
  
  
  RESULTS
  In a large teaching hospital, 179 consecutive CHF patients received CRT-D in 2005-2010. Patients were considered functional responders if left ventricular ejection fraction (LVEF) increased to ≥ 35% postimplantation. Analysis was performed on 142 patients, who had CRT-D as primary prevention, complete data and a baseline LVEF <35%. Endpoints consisted of all-cause mortality, heart failure (HF) hospitalizations, appropriate shocks and inappropriate shocks. Median follow-up was 3.0 years (interquartile range [IQR] 1.6-4.4) and median baseline LVEF was 20% (IQR 18-25%). The functional response-group consisted of 42 patients. In this group no patients died, none were hospitalized for HF, none received appropriate shocks and 3 patients (7.1%) received ≥ 1 inappropriate shocks. In comparison, the functional nonresponse group consisted of 100 patients, of whom 22 (22%) died (P = 0.003), 17 (17%) were hospitalized for HF (P = 0.007), 17 (17%) had ≥ 1 appropriate shocks (P = 0.003) and 8 (8.1%) received ≥ 1 inappropriate shocks (P = 0.78). Multivariable analysis showed that left bundle branch block (LBBB), QRS duration ≥ 150 milliseconds and no need for diuretics at baseline are independent predictors of functional response.
  
  
  CONCLUSIONS
  Functional responders to CRT have a good prognosis and rarely need ICD therapy. LBBB, QRS duration ≥ 150 milliseconds and lack of chronic diuretic use predict functional response.
authors.affiliation: Department of Cardiology, Medical Centre Alkmaar (MCA), Alkmaar, The Netherlands.
authors.forename: Nick
authors.initials: N
authors.lastname: Van Boven
authors.forename: Kjell
authors.initials: K
authors.lastname: Bogaard
authors.forename: Jaap
authors.initials: J
authors.lastname: Ruiter
authors.forename: Geert
authors.initials: G
authors.lastname: Kimman
authors.forename: Dominic
authors.initials: D
authors.lastname: Theuns
authors.forename: Isabella
authors.initials: I
authors.lastname: Kardys
authors.forename: Victor
authors.initials: V
authors.lastname: Umans
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000503:physiopathology / Q000628:therapy; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D058409:Cardiac Resynchronization Therapy Devices; D016009:Chi-Square Distribution; D002908:Chronic Disease; D017147:Defibrillators, Implantable; D004232:Diuretics / Q000627:therapeutic use; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006784:Hospitals, Teaching; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009426:Netherlands; D010359:Patient Readmission; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left
chemical_list: D004232:Diuretics