title: Influence of left ventricular function on outcome of patients treated with implantable defibrillators.
abstract: BACKGROUND
  The outcomes of patients treated with implantable defibrillators were compared between patients with left ventricular ejection fraction greater than or equal to 30% and less than 30%.
  
  
  RESULTS
  Of 68 consecutive patients treated with implantable defibrillators, 40 patients (group 1) had left ventricular ejection fraction greater than or equal to 30%, and 28 patients (group 2) had left ventricular ejection fraction less than 30%. Sudden death, surgical mortality, nonsudden arrhythmia-related death (death within 24 hours after an arrhythmic event despite initial termination of the arrhythmia by the implantable defibrillator), total arrhythmia-related death (including sudden death, surgical death, and nonsudden arrhythmia-related death), and total cardiac death were compared between the two groups. Surgical mortality was 4.4% (0% in group 1, 11% in group 2). During the follow-up of 31 +/- 27 months, actuarial survival rates free of events were 97%, 97%, and 97% in group 1 and 96%, 91%, and 82% in group 2 at 12, 24, and 36 months, respectively, for sudden death (p = NS); 97%, 97%, and 97% in group 1 and 85%, 81%, and 72% in group 2 at 12, 24, and 36 months, respectively, for sudden death and surgical mortality (p less than 0.05); 97%, 97%, and 97% in group 1 and 82%, 78%, and 70% in group 2 at 12, 24, and 36 months, respectively, for total arrhythmia-related death (p less than 0.05); and 95%, 95%, and 95% in group 1 and 82%, 69%, and 57% in group 2 at 12, 24, and 36 months, respectively, for total cardiac death (p less than 0.05). Four (57%) of seven nonsudden cardiac deaths during the initial 36-month follow-up period were causally related to arrhythmia (three surgical deaths and one arrhythmia-related nonsudden death).
  
  
  CONCLUSIONS
  The outcome of patients treated with implantable defibrillators is strongly influenced by the degree of left ventricular dysfunction. In group 1 patients, surgical mortality, sudden death, and total cardiac death are rare. In group 2, sudden death rate may not be markedly different from that of group 1 patients. However, the risk of therapy (surgical mortality) is high. Many nonsudden cardiac deaths are causally related to arrhythmia (surgical mortality or nonsudden arrhythmia-related death). Therefore, the survival rate free of total arrhythmia-related death is significantly lower in group 2 (70% versus 97% in group 1 at 3 years). Further studies are needed to determine the roles of defibrillator therapy and other therapies in various clinical settings.
authors.affiliation: Department of Medicine, Montefiore Medical Center/Moses Division, Bronx, NY 10467.
authors.forename: S G
authors.initials: SG
authors.lastname: Kim
authors.forename: J D
authors.initials: JD
authors.lastname: Fisher
authors.forename: C W
authors.initials: CW
authors.lastname: Choue
authors.forename: J
authors.initials: J
authors.lastname: Gross
authors.forename: J
authors.initials: J
authors.lastname: Roth
authors.forename: K J
authors.initials: KJ
authors.lastname: Ferrick
authors.forename: R
authors.initials: R
authors.lastname: Brodman
authors.forename: S
authors.initials: S
authors.lastname: Furman
mesh_terms: D000206:Actuarial Analysis; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D004554:Electric Countershock / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants; D015996:Survival Rate; D013610:Tachycardia / Q000401:mortality* / Q000628:therapy; D013673:Technology Assessment, Biomedical; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000401:mortality* / Q000628:therapy; D016277:Ventricular Function, Left / Q000502:physiology*