title: Prognostic role of heart rate variability in patients with idiopathic dilated cardiomyopathy.
abstract: BACKGROUND
  The aim of this study was to investigate whether heart rate variability may predict the outcome in patients with idiopathic dilated cardiomyopathy.
  
  
  METHODS
  Time-domain and frequency-domain heart rate variability was analyzed on 24-hour Holter recordings of 56 patients with idiopathic dilated cardiomyopathy (70% males, mean age 49 +/- 16 years; left ventricular ejection fraction 28 +/- 6%).
  
  
  RESULTS
  There were 8 cardiac deaths (14.3%) and 11 arrhythmic events (19.6%, either sudden death or sustained ventricular tachycardia) at a follow-up of 18.5 months (range 3-50 months). Furthermore, 6 patients were included in the list for cardiac transplantation, leading to a prevalence of total cardiac events of 37.5 % (21 patients). All time-domain and most frequency-domain heart rate variability parameters did not show any significant relationship with the end points. However, a low frequency to high frequency (LF/HF) ratio < 1.2 was associated with cardiac death (relative risk-RR 6.8, p < 0.03), arrhythmic events (RR 11.0, p < 0.004), and total cardiac events (RR 4.8, p < 0.002). On the multivariate Cox analysis, no variable showed an independent association with cardiac death, but an LF/HF ratio < 1.2 was the only variable independently predictive of arrhythmic events (RR 8.2, p < 0.02), and the most powerful predictor of total cardiac events (RR 3.8, p < 0.009).
  
  
  CONCLUSIONS
  Our data show that, in patients with idiopathic dilated cardiomyopathy, a low LF/HF ratio, as assessed on 24-hour Holter recordings, is a powerful predictor of cardiac events.
authors.affiliation: Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: G A
authors.initials: GA
authors.lastname: Lanza
authors.forename: M G
authors.initials: MG
authors.lastname: Bendini
authors.forename: A
authors.initials: A
authors.lastname: Intini
authors.forename: G
authors.initials: G
authors.lastname: De Martino
authors.forename: M
authors.initials: M
authors.lastname: Galeazzi
authors.forename: V
authors.initials: V
authors.lastname: Guido
authors.forename: A
authors.initials: A
authors.lastname: Sestito
mesh_terms: D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology