title: Usefulness of heart rate turbulence for predicting cardiac events in patients with nonischemic dilated cardiomyopathy.
abstract: BACKGROUND
  Few studies have described the clinical value of heart rate turbulence (HRT), an autonomic risk stratification index, in stratifying patients with nonischemic dilated cardiomyopathy (NIDCM). We prospectively assessed the utility of HRT for cardiac events in patients with NIDCM.
  
  
  METHODS
  We enrolled 134 consecutive patients with NIDCM. Heart rate turbulence was automatically measured using an algorithm based on 24-hour Holter electrocardiograms. In addition to HRT, other risk indices such as a reduced left ventricular ejection fraction of 30% or less, the presence of nonsustained ventricular tachycardia (VT), the use of medical treatment, and so on were assessed as well. The primary end point was defined as cardiac mortality and sustained VTs.
  
  
  RESULTS
  Of the patients enrolled, 106 (79%) were used for HRT assessment. Heart rate turbulence was determined as positive in 26 patients (25%) and negative in 80 patients (75%). During a follow-up of 445 ± 216 days, 23 patients (23%) reached the primary end point. Among indices, documented presence of nonsustained VT and an HRT-positive outcome had significant values with the primary end point (P = .02 and P = .0001, respectively). On multivariate analysis, an HRT-positive outcome was the most significant predictor, with a hazard ratio of 4.5 (95% confidence interval, 2.0-10.4; P = .0004).
  
  
  CONCLUSIONS
  Heart rate turbulence is a powerful risk stratification index for cardiac events defined as cardiac mortality and sustained VTs in patients with NIDCM.
authors: Department of Cardiovascular Medicine, Toho University Medical Center, Tokyo, Japan. ikety3@gmail.com
authors: Takanori
authors: T
authors: Ikeda
authors: Yosuke
authors: Y
authors: Miwa
authors: Atsuko
authors: A
authors: Abe
authors: Kazuo
authors: K
authors: Nakazawa
mesh_terms: D000465:Algorithms; D002311:Cardiomyopathy, Dilated / Q000150:complications*; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D015716:Electrocardiography, Ambulatory; D006339:Heart Rate / Q000502:physiology*; D011446:Prospective Studies; D013318:Stroke Volume / Q000502:physiology; D017180:Tachycardia, Ventricular / Q000175:diagnosis*; D016277:Ventricular Function, Left / Q000502:physiology