title: Heart rate turbulence and variability in patients with ventricular arrhythmias.
abstract: BACKGROUND
  To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV) and heart rate turbulence (HRT) in patients with ventricular tachycardia or fibrillation (Group I; n=6), non sustained ventricular tachycardia (Group II; n=32), frequent premature ventricular beats (Group III; n=26) and with ICD implantation (Group IV; n=11).
  
  
  METHODS
  Time domain parameters of HRV and turbulence onset (TO) and slope (TS) were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO <0% and TS >2.5 msec/RR-I for HRT.
  
  
  RESULTS
  Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I.
  
  
  CONCLUSIONS
  These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias.
authors: Cardiology, Department of Medicine, Surgery and Odontology, San Paolo Hospital, University of Milan - Italy.
authors: Federico
authors: F
authors: Lombardi
authors: Fabrizio
authors: F
authors: Tundo
authors: Abdalrahim
authors: A
authors: Abukwaik
authors: Diego
authors: D
authors: Tarricone