title: Multiple autonomic and repolarization investigation of sudden cardiac death in dilated cardiomyopathy and controls.
abstract: BACKGROUND
  Prophylactic defibrillator implantation is recommended in dilated, nonischemic heart disease and left ventricular ejection fraction of ≤0.30 to 0.35. Noninvasive testing should improve accuracy in decision making of prophylactic defibrillator implantation.
  
  
  RESULTS
  We enrolled 60 patients (median age, 57 years) with dilated cardiomyopathy and left ventricular ejection fraction ≤0.50, and 30 control subjects (median age, 59 years) with left ventricular ejection fraction >0.50. The protocol included an initial assessment, a second assessment after 3 years, and a final follow-up: pharmacological baroreflex testing (baroreceptor reflex sensitivity), short-term spectral analysis of heart rate variability (low frequency/high frequency), and long-term time domain analysis (SD of all normal-to-normal R-R intervals), exercise microvolt T wave alternans, and signal-averaged ECG, and corrected QT-time. The median follow-up was 7 years. End points were cardiac death, resuscitated cardiac arrest, and arrhythmic death. Cardiac death was observed in 21 patients. Resuscitated cardiac arrest and arrhythmic death caused by ventricular tachyarrhythmias ≥240 per minute was observed in 7 and 10 patients, respectively. In the single time point analysis, microvolt T wave alternans, baroreceptor reflex sensitivity, and SD of all normal-to-normal R-R intervals at initial testing added significant information regarding cardiac death. Microvolt T wave alternans added information on resuscitated cardiac arrest or arrhythmic death at multiple time points (P<0.001). False-negative microvolt T wave alternans results were seen in 8% of patients.
  
  
  CONCLUSIONS
  Noninvasive testing and left ventricular ejection fraction could not reliably identify patients with dilated cardiomyopathy at risk of fatal ventricular tachyarrhythmias. Therefore, the strategy to confine prophylactic implantable cardioverter-defibrillator implantation to patients with dilated cardiomyopathy and severely reduced LV function should be reconsidered.
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.). thomas.pezawas@meduniwien.ac.at.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pezawas
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: André
authors.initials: A
authors.lastname: Diedrich
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: Robert
authors.initials: R
authors.lastname: Winker
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: David
authors.initials: D
authors.lastname: Robertson
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: Bernhard
authors.initials: B
authors.lastname: Richter
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Byrne
authors.affiliation: From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).
authors.forename: Herwig
authors.initials: H
authors.lastname: Schmidinger
mesh_terms: D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D017704:Baroreflex; D001794:Blood Pressure; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy; D016022:Case-Control Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control; D003661:Decision Support Techniques; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D011322:Primary Prevention / Q000295:instrumentation; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D055815:Young Adult
keywords: (non-invasive) risk stratification; cardiomyopathy; dilated; implantable cardioverter defibrillator; sudden cardiac death or arrhythmic death