title: Heart rate turbulence slope reduction in imminent ventricular tachyarrhythmia and its implications.
abstract: BACKGROUND
  The aim of this study was to see whether heart rate turbulence (HRT) parameters change preceding imminent ventricular tachyarrhythmias (VT/VF).
  
  
  RESULTS
  The Spontaneous Ventricular Tachyarrhythmia Database (Medtronic Version 1.0) consisting of 83 paired (control and pre-VT/VF) sets of 1,000 RR intervals recorded by the Medtronic Jewel Plus ICD was used. Sixty-one control records and 69 pre-VT/VF records had two or more ectopic beats, allowing calculation of six HRT indices: means and standard deviations (SD) of turbulence slope (TS), turbulence onset (TO), and turbulence timing (TT). The only index found to be different between control and pre-VT/VF records was SD of TS (4.2 +/- 3.0 control vs 3.1 +/- 1.9 pre-VT/VF, P < 0.05). Thirty-one datasets classified as having normal HRT in control demonstrated a decrease of both TS mean (P < 0.01) and SD (P < 0.01), and loss of correlation between TS mean and left ventricular ejection fraction (LVEF) preceding VT/VF (P < 0.0001 control, P = 0.8 pre-VT/VF).
  
  
  CONCLUSIONS
  Both mean and SD of TS are reduced before VT/VF, but only in patients who have normal baseline HRT, and are capable of manifesting reduction. This may be why previous studies could not agree on pre-arrhythmia characteristics.
authors.affiliation: Internal Medicine Department, Munich University of Technology, Munich, Germany. watanabe@slu.edu
authors.forename: Mari A
authors.initials: MA
authors.lastname: Watanabe
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D017147:Defibrillators, Implantable; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000628:therapy