title: Three years of cardiac resynchronization therapy: could superior benefits be obtained in patients with heart failure and narrow QRS?
abstract: OBJECTIVE
  To examine the long-term effects of cardiac resynchronization therapy (CRT) in patients presenting with heart failure (HF) and QRS </= 120 ms.
  
  
  METHODS
  This was a prospective, longitudinal study of 376 patients [mean age = 65 years, mean left ventricular (LV) ejection fraction (EF) = 29%, mean QRS duration = 165 ms, mean distance covered during a 6-minute hall walk (6-MHW) = 325 m], who underwent successful implantation of CRT systems. The QRS duration at baseline was </= 120 ms in 45 patients (12%) who were not pre-selected by echocardiographic criteria of dyssynchrony, and > 120 ms in the remaining 331 patients. The baseline characteristics of the 2 groups were similar. We evaluated indices of cardiac function, percentage of responders, and survival rates over a mean 28-month follow-up.
  
  
  RESULTS
  Both groups experienced similar long-term increases in 6-MHW, and decreases in New York Heart Association functional class and LV end-systolic volume (all comparisons P < 0.0001 in both groups). Time interaction of changes in LVEF and percentage of responders were significantly different (P = 0.03 and P = 0.004, respectively), in favor of the narrow QRS group, where the changes were sustained and persisted at 2 and 3 years. The long-term death rate from HF was lower in the group with narrow than in the group with wide QRS complex (P = 0.04; log-rank test).
  
  
  CONCLUSIONS
  CRT confers considerable long-term clinical, functional, and survival benefits in patients presenting with HF and narrow QRS, not preselected by echocardiographic criteria of dyssynchrony. Caution is advised before denying CRT to these patients on the basis of QRS width only.
authors.affiliation: IRCCS Istituto Clinico Humanitas, Rozzano-Milano, Italy. maurizio.gasparini@humanitas.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gasparini
authors.forename: François
authors.initials: F
authors.lastname: Regoli
authors.forename: Paola
authors.initials: P
authors.lastname: Galimberti
authors.forename: Carlo
authors.initials: C
authors.lastname: Ceriotti
authors.forename: Marika
authors.initials: M
authors.lastname: Bonadies
authors.forename: Maurizio
authors.initials: M
authors.lastname: Mangiavacchi
authors.forename: Bruno
authors.initials: B
authors.lastname: Andreuzzi
authors.forename: Renato
authors.initials: R
authors.lastname: Bragato
authors.forename: Daniela
authors.initials: D
authors.lastname: Pini
authors.forename: Catherine
authors.initials: C
authors.lastname: Klersy
authors.forename: Edoardo
authors.initials: E
authors.lastname: Gronda
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left