title: Changes in Follow-Up Left Ventricular Ejection Fraction Associated With Outcomes in Primary Prevention Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Device Recipients.
abstract: BACKGROUND
  Heart failure patients with primary prevention implantable cardioverter-defibrillators (ICD) may experience an improvement in left ventricular ejection fraction (LVEF) over time. However, it is unclear how LVEF improvement affects subsequent risk for mortality and sudden cardiac death.
  
  
  OBJECTIVE
  This study sought to assess changes in LVEF after ICD implantation and the implication of these changes on subsequent mortality and ICD shocks.
  
  
  METHODS
  We conducted a prospective cohort study of 538 patients with repeated LVEF assessments after ICD implantation for primary prevention of sudden cardiac death. The primary endpoint was appropriate ICD shock defined as a shock for ventricular tachyarrhythmias. The secondary endpoint was all-cause mortality.
  
  
  RESULTS
  Over a mean follow-up of 4.9 years, LVEF decreased in 13.0%, improved in 40.0%, and was unchanged in 47.0% of the patients. In the multivariate Cox models comparing patients with an improved LVEF with those with an unchanged LVEF, the hazard ratios were 0.33 (95% confidence interval: 0.18 to 0.59) for mortality and 0.29 (95% confidence interval: 0.11 to 0.78) for appropriate shock. During follow-up, 25% of patients showed an improvement in LVEF to >35% and their risk of appropriate shock decreased but was not eliminated.
  
  
  CONCLUSIONS
  Among primary prevention ICD patients, 40.0% had an improved LVEF during follow-up and 25% had LVEF improved to >35%. Changes in LVEF were inversely associated with all-cause mortality and appropriate shocks for ventricular tachyarrhythmias. In patients whose follow-up LVEF improved to >35%, the risk of an appropriate shock remained but was markedly decreased.
authors.affiliation: Department of Epidemiology and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Yiyi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Elena
authors.initials: E
authors.lastname: Blasco-Colmenares
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Butcher
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Sanaz
authors.initials: S
authors.lastname: Norgard
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Victor
authors.initials: V
authors.lastname: Nauffal
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
authors.affiliation: Washington Hospital Center, Washington, DC.
authors.forename: Zayd
authors.initials: Z
authors.lastname: Eldadah
authors.affiliation: University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Timm
authors.initials: T
authors.lastname: Dickfeld
authors.affiliation: Virginia Commonwealth University School of Medicine, Richmond, Virginia.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Ellenbogen
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Gordon F
authors.initials: GF
authors.lastname: Tomaselli
authors.affiliation: Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: alcheng@jhmi.edu.
authors.forename: Alan
authors.initials: A
authors.lastname: Cheng
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods / Q000706:statistics & numerical data; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000628:therapy; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D013318:Stroke Volume; D014481:United States / Q000453:epidemiology; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology / Q000401:mortality
keywords: all-cause mortality; shock; sudden cardiac death