title: Implantable cardioverter defibrillator therapy activation for high risk patients with relatively well preserved left ventricular ejection fraction. Does it really work?
abstract: BACKGROUND
  Current guidelines for the primary prevention of sudden cardiac death have used a left ventricular ejection fraction (LVEF) ≤ 35% as a critical point to justify implantable cardioverter defibrillator (ICD) implantation in post myocardial infarction patients and in those with nonischemic dilated cardiomyopathy. We compared mortality and ICD activation rates among different ICD group recipients using a cut-off value for LVEF ≤ 35%.
  
  
  METHODS
  We followed up for a mean period of 41.1 months 495 ICD recipients (442 males, 65.6 years old, 68.9% post myocardial infarction patients, 422 with LVEF ≤ 35%). Prevention was considered primary in patients who fulfilled guidelines criteria or had inducible ventricular arrhythmia during programmed ventricular stimulation for patients with LVEF >35%.
  
  
  RESULTS
  Over the course of the trial, 84 of 495 patients died; 69 experienced cardiac death (6 sudden) and 15 non cardiac death. ICD recipients with LVEF ≤ 35% compared to those with preserved LVEF (mean LVEF=43%) had a greater incidence of total mortality (18% vs. 11%, log rank p=0.028) and cardiac death (15.4% vs. 5.5%, log rank p=0.005). There was no difference in the incidence for appropriate device therapy between patients with LVEF ≤ 35% and those with LVEF >35% (56.9% vs. 65.8%, log rank p=0.93). In the multivariate analysis the presence of advanced New York Heart Association stage predicted both total mortality (HR=2.69, 95% CI 1.771-4.086) and cardiac death (HR=3.437, 95% CI 2.163-5.463).
  
  
  CONCLUSIONS
  ICD therapy may protect heart failure patients at early stages from arrhythmic morbidity and mortality, based on an electrophysiology-guided risk stratification approach.
authors.affiliation: First Cardiology Department, University of Athens Medical School, Hippokration Hospital, Athens, Greece. kgatzoul@med.uoa.gr
authors.forename: Konstantinos A
authors.initials: KA
authors.lastname: Gatzoulis
authors.forename: Dimitris
authors.initials: D
authors.lastname: Tsiachris
authors.forename: Polichronis
authors.initials: P
authors.lastname: Dilaveris
authors.forename: Stefanos
authors.initials: S
authors.lastname: Archontakis
authors.forename: Petros
authors.initials: P
authors.lastname: Arsenos
authors.forename: Apostolis
authors.initials: A
authors.lastname: Vouliotis
authors.forename: Skevos
authors.initials: S
authors.lastname: Sideris
authors.forename: George
authors.initials: G
authors.lastname: Trantalis
authors.forename: Efstathios
authors.initials: E
authors.lastname: Kartsagoulis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Kallikazaros
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Stefanadis
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*