title: Clinical and electrocardiographic predictors of a positive response to cardiac resynchronization therapy in advanced heart failure.
abstract: OBJECTIVE
  Cardiac resynchronization therapy (CRT) is an effective treatment for refractory congestive heart failure (CHF). However, up to 30% of patients do not respond to CRT. The aim of this study was to identify clinical and electrocardiographic (ECG) predictors of a positive response to CRT.
  
  
  RESULTS
  This retrospective study included 139 consecutive patients successfully implanted with a CRT device (mean age, 68+/-9 years, 113 men). At baseline, 69% of patients were in New York Heart Association (NYHA) functional class III, and 31% in class IV, mean left ventricular ejection fraction was 21+/-6%, and mean QRS duration was 188+/-28 ms. In each patient, left and right ventricular leads were placed to attain the shortest QRS duration during biventricular stimulation. Patients were classified at 6 months as responders to CRT (n=100) if they were alive, they had not been re-hospitalized for management of CHF, and the NYHA class had decreased by 1 point, and/or peak VO(2) or 6 min hall-walk increased by >10%. All others were classified as non-responders (n=38; one patient was lost to follow-up). Uni- and multivariate logistic regression analyses were performed to detect a pre- or intra-operative predictor of a positive response to CRT. Among multiple demographic, clinical, and ECG variables, the amount of QRS shortening (DeltaQRS) associated with biventricular stimulation was the only independent predictor of a positive (37+/-23 ms) vs. negative (11+/-23 ms) response to CRT (P<0.001).
  
  
  CONCLUSIONS
  A positive response to CRT was observed in 73% of patients at 6 months and predicted only by DeltaQRS.
authors.affiliation: Department of Cardiology, Centre Hospitalier Universitaire, Rennes F-35000, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lecoq
authors.forename: Christophe
authors.initials: C
authors.lastname: Leclercq
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Leray
authors.forename: Christophe
authors.initials: C
authors.lastname: Crocq
authors.forename: Christine
authors.initials: C
authors.lastname: Alonso
authors.forename: Christian
authors.initials: C
authors.lastname: de Place
authors.forename: Philippe
authors.initials: P
authors.lastname: Mabo
authors.forename: Claude
authors.initials: C
authors.lastname: Daubert
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002908:Chronic Disease; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome