title: The impact of age and gender on cardiac resynchronization therapy outcome.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) outcome varies significantly among patients. We aimed to determine the impact of age, gender, and heart failure etiology on the long-term outcome of patients receiving CRT.
  
  
  METHODS
  A total of 117 patients with drug-refractory heart failure, New York Heart Association (NYHA) Class III or IV, and a wide QRS complex, who received CRT, were followed for one year. Long-term outcome was measured as a combined end point of hospitalization for heart failure and/or all cause mortality. Efficacy of CRT was compared between men and women, between older and younger patients, and between patients with ischemic and nonischemic heart disease. Time to the primary end point was estimated by the Kaplan-Meier method and comparisons were made using the Breslow-Wilcoxon test.
  
  
  RESULTS
  Baseline clinical characteristics were comparable between gender, age, and heart failure etiology subgroups. There was no significant difference in the combined end point between older versus younger (age >70, (n = 71), versus age < 70, (n = 46), P = 0.52); both genders (men, n = 91 vs women, n = 26, P = 0.46) and etiology of the cardiomyopathy (ischemic (n = 79) vs nonischemic (n = 38), P = 0.12). Substratification of the genders by the etiology of the cardiomyopathy, showed that women with ischemic cardiomyopathy (IW, n = 10) had a trend to a worse outcome compared to the other groups i.e., nonischemic women (NIW, n = 16), ischemic men (IM, n = 69), and nonischemic men (NIM, n = 22), P = 0.04. After adjusting for potential covariates, a Cox regression analysis showed no significant difference between the groups (P = 0.61).
  
  
  CONCLUSIONS
  CRT outcome appears independent of age, gender, and heart failure etiology in this single institution study.
authors.affiliation: Cardiac Arrhythmia Service, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
authors.forename: Omeed
authors.initials: O
authors.lastname: Zardkoohi
authors.forename: Veena
authors.initials: V
authors.lastname: Nandigam
authors.forename: Lorne
authors.initials: L
authors.lastname: Murray
authors.forename: E Kevin
authors.initials: EK
authors.lastname: Heist
authors.forename: Theofanie
authors.initials: T
authors.lastname: Mela
authors.forename: Mary
authors.initials: M
authors.lastname: Orencole
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Ruskin
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
mesh_terms: D017677:Age Distribution; D000368:Aged; D002303:Cardiac Output, Low / Q000453:epidemiology* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D017678:Sex Distribution; D016896:Treatment Outcome