title: Depressed low frequency power of heart rate variability as an independent predictor of sudden death in chronic heart failure.
abstract: OBJECTIVE
  Identification of patients with chronic heart failure at risk for sudden death remains difficult. We sought to assess the prognostic value for all-cause and sudden death of time and frequency domain measures of heart rate variability in chronic heart failure.
  
  
  RESULTS
  We prospectively enrolled 190 patients with chronic heart failure in sinus rhythm, mean age 61+/-12 years, 109 (57.4%) in NYHA class II and 81 (42.6%) in classes III or IV, mean cardiothoracic ratio 57.6+/-6.4% and mean left ventricular ejection fraction 28.2+/-8.8%, 85 (45%) with ischaemic and 105 (55%) with idiopathic dilated cardiomyopathy. Time and frequency domain measures of heart rate variability were obtained from 24 h Holter ECG recordings, spectral measures were averaged for calculation of daytime (1000h-1900h) and night-time (2300h-0600h) values. During follow-up (22+/-18 months), 55 patients died, 21 of them suddenly and two presented with a syncopal spontaneous sustained ventricular tachycardia. In multivariate analysis, independent predictors for all-cause mortality were: ischaemic heart disease, cardiothoracic ratio > or =60% and standard deviation of all normal RR intervals <67 ms (RR = 2.5, 95% CI 1.5-4.2). Independent predictors of sudden death were: ischaemic heart disease and daytime low frequency power <3.3 ln (ms(2)) (RR = 2.8, 95% CI 1.2-8.6).
  
  
  CONCLUSIONS
  Depressed heart rate variability has independent prognostic value in patients with chronic heart failure; spectral analysis identifies an increased risk for sudden death in these patients.
authors.affiliation: Department of Cardiology, Rangueil University Hospital, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Galinier
authors.forename: A
authors.initials: A
authors.lastname: Pathak
authors.forename: J
authors.initials: J
authors.lastname: Fourcade
authors.forename: C
authors.initials: C
authors.lastname: Androdias
authors.forename: D
authors.initials: D
authors.lastname: Curnier
authors.forename: S
authors.initials: S
authors.lastname: Varnous
authors.forename: S
authors.initials: S
authors.lastname: Boveda
authors.forename: P
authors.initials: P
authors.lastname: Massabuau
authors.forename: M
authors.initials: M
authors.lastname: Fauvel
authors.forename: J M
authors.initials: JM
authors.lastname: Senard
authors.forename: J P
authors.initials: JP
authors.lastname: Bounhoure
mesh_terms: D001145:Arrhythmias, Cardiac / Q000150:complications*; D002303:Cardiac Output, Low / Q000401:mortality*; D002908:Chronic Disease; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis