title: Survival and appropriate device interventions in recipients of cardioverter defibrillators implanted for the primary versus secondary prevention of sudden cardiac death.
abstract: BACKGROUND
  Implantable cardioverter-defibrillators (ICD) implanted after an episode of ventricular tachyarrhythmia (VTA) or in patients at high risk of VTA lower the long-term mortality. Comparisons of the clinical outcomes of the two indications are scarce.
  
  
  METHODS
  The study enrolled 360 consecutive ICD recipients. The device was implanted for secondary prevention in 150 patients, whose mean age was 60 +/- 14 years, and mean left ventricular ejection fraction (LVEF) was 40 +/- 16%, and for primary prevention in 210 patients, whose mean age was 61 +/- 11 years, and mean LVEF was 31 +/- 13%. All-cause mortality and time to first appropriate ICD therapy were measured.
  
  
  RESULTS
  The two study groups were similar with respect to age and prevalence of coronary artery disease. Mean LVEF was higher in the secondary prevention group (P = 0.001). Cox regression analysis revealed a significantly shorter time to first appropriate ICD therapy in the secondary prevention group (HR = 0.51, 95% CI = 0.30 - 0.87, P = 0.01). Over a mean follow-up of 37 +/- 19 months, the all-cause mortality in the overall population was 12.7%, and was similar in both subgroups (HR = 0.99, 95% CI = 0.55-1.77, P = 0.97).
  
  
  CONCLUSIONS
  The long-term mortality in this unselected population of ICD recipients was low. Patients treated for secondary prevention received earlier appropriate ICD therapy than patients treated for primary prevention. Long-term mortality was similar in both groups. The higher VT incidence of VTA was effectively treated by the ICD and was not associated with a higher mortality.
authors.affiliation: Charité- Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Medizinische Klinik mit Schwerpunkt Kardiologie, Berlin, Germany. martin.stockburger@charite.de
authors.forename: Martin
authors.initials: M
authors.lastname: Stockburger
authors.forename: Alice
authors.initials: A
authors.lastname: Krebs
authors.forename: Aischa
authors.initials: A
authors.lastname: Nitardy
authors.forename: Dirk
authors.initials: D
authors.lastname: Habedank
authors.forename: Ozlem
authors.initials: O
authors.lastname: Celebi
authors.forename: Thomas
authors.initials: T
authors.lastname: Knaus
authors.forename: Rainer
authors.initials: R
authors.lastname: Dietz
mesh_terms: D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004554:Electric Countershock / Q000295:instrumentation / Q000401:mortality*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000401:mortality* / Q000517:prevention & control*; D016896:Treatment Outcome