title: Heart rate variability in idiopathic dilated cardiomyopathy: characteristics and prognostic value.
abstract: OBJECTIVE
  This study was designed to evaluate heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (IDC), to determine its correlation with hemodynamic variables and ventricular arrhythmias and to evaluate its prognostic value in IDC.
  
  
  BACKGROUND
  Previous studies have shown that HRV could predict arrhythmic events in patients after infarction, but the characteristics of HRV in IDC have not been fully established.
  
  
  METHODS
  Time domain analysis of HRV on 24-h electrocardiographic (ECG) recording was performed in 93 patients with IDC, and results were compared with those in 63 control subjects.
  
  
  RESULTS
  Patients with IDC, even those without congestive heart failure, had significantly lower values for HRV than those of control subjects. HRV was related to left ventricular shortening fraction (R = 0.5, p = 0.0001) and to peak oxygen uptake (R = 0.53, p = 0.01). HRV was not different in patients with runs of ventricular tachycardia or in patients with late potentials on the signal-averaged ECG. During a mean follow-up period (+/-SD) of 49.5 +/- 35.6 months, patients with reduced HRV had an increased risk of cardiac death or heart transplantation (p = 0.006). On multivariate analysis, cardiac events were predicted by increased left ventricular end-diastolic diameter (p = 0.0001), reduced standard deviation of all normal to normal RR intervals (p = 0.02) and increased pulmonary capillary wedge pressure (p = 0.04).
  
  
  CONCLUSIONS
  Decreased HRV in patients with IDC is related to left ventricular dysfunction and not to ventricular arrhythmias. Analysis of HRV can identify patients with IDC who have an increased risk of cardiac death or heart transplantation.
authors.affiliation: Cardiology B and Electrophysiology Department, Hospital Trousseau, Tours, France. lfau@med.univ.tours.fr
authors.forename: L
authors.initials: L
authors.lastname: Fauchier
authors.forename: D
authors.initials: D
authors.lastname: Babuty
authors.forename: P
authors.initials: P
authors.lastname: Cosnay
authors.forename: M L
authors.initials: ML
authors.lastname: Autret
authors.forename: J P
authors.initials: JP
authors.lastname: Fauchier
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D002311:Cardiomyopathy, Dilated / Q000150:complications* / Q000401:mortality / Q000503:physiopathology*; D016022:Case-Control Studies; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000209:etiology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D011379:Prognosis; D011669:Pulmonary Wedge Pressure; D013318:Stroke Volume; D016019:Survival Analysis; D018487:Ventricular Dysfunction, Left / Q000209:etiology*