title: Conventional heart rate variability analysis of ambulatory electrocardiographic recordings fails to predict imminent ventricular fibrillation.
abstract: OBJECTIVE
  The purpose of this report was to study heart rate variability in Holter recordings of patients who experienced ventricular fibrillation during the recording.
  
  
  BACKGROUND
  Decreased heart rate variability is recognized as a long-term predictor of overall and arrhythmic death after myocardial infarction. It was therefore postulated that heart rate variability would be lowest when measured immediately before ventricular fibrillation.
  
  
  METHODS
  Conventional indexes of heart rate variability were calculated from Holter recordings of 24 patients with structural heart disease who had ventricular fibrillation during monitoring. The control group consisted of 19 patients with coronary artery disease, of comparable age and left ventricular ejection fraction, who had nonsustained ventricular tachycardia but no ventricular fibrillation.
  
  
  RESULTS
  Heart rate variability did not differ between the two groups, and no consistent trends in heart rate variability were observed before ventricular fibrillation occurred.
  
  
  CONCLUSIONS
  Although conventional heart rate variability is an independent long-term predictor of adverse outcome after myocardial infarction, its clinical utility as a short-term predictor of life-threatening arrhythmias remains to be elucidated.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, Texas.
authors.forename: T
authors.initials: T
authors.lastname: Vybiral
authors.forename: D H
authors.initials: DH
authors.lastname: Glaeser
authors.forename: A L
authors.initials: AL
authors.lastname: Goldberger
authors.forename: D R
authors.initials: DR
authors.lastname: Rigney
authors.forename: K R
authors.initials: KR
authors.lastname: Hess
authors.forename: J
authors.initials: J
authors.lastname: Mietus
authors.forename: J E
authors.initials: JE
authors.lastname: Skinner
authors.forename: M
authors.initials: M
authors.lastname: Francis
authors.forename: C M
authors.initials: CM
authors.lastname: Pratt
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000503:physiopathology