title: Risk of arrhythmic death in ischemic heart disease: a prospective, controlled, observer-blind risk stratification over 10 years.
abstract: BACKGROUND
  Risk of arrhythmic death is considered highest in ischemic heart disease with severe left ventricular ejection fraction (LVEF) reduction. Non-invasive testing should improve decision-making of prophylactic defibrillator (ICD) implantation.
  
  
  METHODS
  We enrolled 120 patients with ischemic heart disease and LVEF < 50% and 30 control subjects without ischemic heart disease and normal LVEF. An initial assessment, a second assessment after 3 years and a final follow-up comprised of pharmacological baroreflex testing (BRS), short-term spectral [low-frequency (LF) to high-frequency (HF) ratio] and long-term time-domain analysis of heart rate variability (SDNN), exercise Microvolt T-wave alternans (MTWA) and others.
  
  
  RESULTS
  The median follow-up was 7·5 years. Resuscitated cardiac arrest and arrhythmic death due to ventricular arrhythmias ≥ 240/min was observed in 18% and 15% of patients, respectively. Cardiac death was observed in 28% of patients. The incidence of arrhythmic death and resuscitated cardiac arrest was identical in patients with ischemic heart disease with LVEF < 30% and ≥ 30%. No significant difference between subgroups with LVEF of < 30%, 30-39% and ≥ 40% was found either. MTWA, BRS, SDNN and LF to HF ratio failed to identify patients at risk of arrhythmic death in a multiple regression model.
  
  
  CONCLUSIONS
  Ischemic heart disease patients with LVEF < 30% and ≥ 30% face the same risk of arrhythmic death. Stratification techniques fail to identify high-risk patients. Therefore, the current practice to constrain prophylactic ICDs to patients with severely reduced LVEF seems to be insufficient.
authors.affiliation: Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pezawas
authors.affiliation: Departments of Medicine, Clinical Pharmacology, Pharmacology, and Neurology, Vanderbilt Autonomic Dysfunction Center, Nashville, TN, USA.
authors.forename: André
authors.initials: A
authors.lastname: Diedrich
authors.affiliation: Departments of Medicine, Clinical Pharmacology, Pharmacology, and Neurology, Vanderbilt Autonomic Dysfunction Center, Nashville, TN, USA.
authors.forename: David
authors.initials: D
authors.lastname: Robertson
authors.affiliation: Health and Prevention Center, Hera, Vienna, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Winker
authors.affiliation: Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Richter
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors.forename: Herwig
authors.initials: H
authors.lastname: Schmidinger
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000401:mortality; D016022:Case-Control Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications* / Q000401:mortality; D011446:Prospective Studies; D018570:Risk Assessment; D016037:Single-Blind Method; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*
keywords: Ischemic heart disease; non-invasive risk stratification; sudden cardiac death