title: Reduced cardio-respiratory coupling in acute alcohol withdrawal.
abstract: BACKGROUND
  Chronic alcoholism represents a risk factor for cardiac arrhythmias. One underlying mechanism is a sympathetically dominated autonomic imbalance. This is especially apparent during acute withdrawal from alcohol. Since linear analysis of heart rate variability may not be entirely adequate to detect such autonomic dysfunction in acute alcohol withdrawal, we applied novel non-linear parameters and measures for cardio-respiratory coupling.
  
  
  METHODS
  20 patients suffering from acute alcohol withdrawal syndrome and 20 controls were included. For patients, heart rate and respiration were recorded on admission, after medication and at discharge. From these data, complexity measures (symbolic dynamics, approximate entropy) of heart rate modulation and respiration as well as parameters for cardio-respiratory coupling (coherence, cross-approximate entropy) which relate to vagal function were calculated.
  
  
  RESULTS
  Heart rate modulation was significantly less complex in patients acutely admitted for alcohol withdrawal. Furthermore, coupling between beat-to-beat (RR) intervals and respiration time series was significantly diminished. Of the parameters assessed, cross-approximate entropy showed a trend for correlation with symptom severity.
  
  
  CONCLUSIONS
  These data indicate diminished vagal function in acute alcohol withdrawal. Applying the methods described thus allows a sensitive detection of vagal neuropathy in this disease.
authors.affiliation: Department of Psychiatry, Friedrich-Schiller-University, Philosophenweg 3, Jena, Germany. Karl-Juergen.Baer@med.uni-jena.de
authors.forename: Karl-Jürgen
authors.initials: KJ
authors.lastname: Bär
authors.forename: Michael Karl
authors.initials: MK
authors.lastname: Boettger
authors.forename: Steffen
authors.initials: S
authors.lastname: Schulz
authors.forename: Rene
authors.initials: R
authors.lastname: Neubauer
authors.forename: Thomas
authors.initials: T
authors.lastname: Jochum
authors.forename: Andreas
authors.initials: A
authors.lastname: Voss
authors.forename: Vikram K
authors.initials: VK
authors.lastname: Yeragani
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000523:psychology; D000465:Algorithms; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D002492:Central Nervous System Depressants / Q000009:adverse effects*; D002719:Chlormethiazole / Q000627:therapeutic use; D019277:Entropy; D000431:Ethanol / Q000009:adverse effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use; D008297:Male; D015999:Multivariate Analysis; D011569:Psychiatric Status Rating Scales; D015656:Respiratory Mechanics / Q000187:drug effects*; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy / Q000503:physiopathology*; D014630:Vagus Nerve / Q000503:physiopathology
chemical_list: D002492:Central Nervous System Depressants; D006993:Hypnotics and Sedatives; D002719:Chlormethiazole; D000431:Ethanol