title: The benefits of biventricular pacing in heart failure patients with narrow QRS, NYHA class II and right ventricular pacing.
abstract: OBJECTIVE
  To identify subgroups of heart failure patients who might benefit from biventricular pacing.
  
  
  BACKGROUND
  Cardiac resynchronization therapy (CRT) improves the quality of life, New York Heart Association (NYHA) functional class, and exercise capacity and decreases hospitalizations for heart failure for patients who have severe heart failure and a wide QRS. It is unclear if other populations of heart failure patients would benefit from CRT.
  
  
  METHODS
  One hundred forty-four consecutive heart failure patients who underwent CRT and completed 3 months of follow-up were reviewed. Demographic, echocardiographic, electrocardiographic, and clinical outcome data were analyzed to assess the relationship of functional class and QRS duration before device implantation to postimplant outcomes.
  
  
  RESULTS
  There were 20, 88, and 36 patients in NYHA functional class II, III, and IV, respectively. Thirty-four patients had right ventricular pacing and another 29 patients had a QRS duration < or = 150 ms. Patients who were in NYHA functional class II at baseline had significant improvement in left ventricular ejection fraction and indices of left ventricular remodeling after CRT. Similar significant findings were seen in the subgroup with right ventricular pacing at baseline after CRT. However, in the subgroup with a narrow QRS duration, there were no significant changes in the indices of left ventricular remodeling or in the NYHA functional class and there was a significant increase in the QRS duration. For the study cohort as a whole, an improvement in NYHA functional class after CRT correlated with a significant decrease in adverse clinical outcomes.
  
  
  CONCLUSIONS
  Heart failure patients who were in NYHA functional class II and those with right ventricular pacing appeared to benefit from CRT.
authors.affiliation: Division of Medicine, Department of Cardiovascular Medicine, The Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ng
authors.forename: Navin
authors.initials: N
authors.lastname: Kedia
authors.forename: David
authors.initials: D
authors.lastname: Martin
authors.forename: Patrick
authors.initials: P
authors.lastname: Tchou
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
authors.forename: Bruce
authors.initials: B
authors.lastname: Wilkoff
authors.forename: Randall
authors.initials: R
authors.lastname: Starling
authors.forename: Richard A
authors.initials: RA
authors.lastname: Grimm
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods* / Q000706:statistics & numerical data*; D015897:Comorbidity; D005260:Female; D006333:Heart Failure / Q000453:epidemiology* / Q000517:prevention & control*; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000453:epidemiology* / Q000517:prevention & control*