title: Risk stratification for serious arrhythmic events using nonsustained ventricular tachycardia and heart rate turbulence detected by 24-hour holter electrocardiograms in patients with left ventricular dysfunction.
abstract: BACKGROUND
  Previous studies have described the clinical usefulness of the presence of nonsustained ventricular tachycardia (NSVT) and defined heart rate turbulence (HRT) in stratifying patients at risk. We prospectively assessed whether HRT can facilitate the predictive accuracy of NSVT for identifying patients at risk for serious arrhythmic events in patients with left ventricular (LV) dysfunction.
  
  
  METHODS
  We enrolled 299 consecutive patients with LV dysfunction (ejection fraction ≤ 40%) including ischemic (n = 184) and nonischemic causes (n = 115). The presence of NSVT was assessed on Holter electrocardiograms (ECGs). HRT was simultaneously measured from Holter ECGs, assessing two parameters: turbulence onset (TO) and turbulence slope (TS). HRT was considered positive when both TO and TS were abnormal. The end point was defined as of sudden cardiac death (SCD) and sustained ventricular tachyarrhythmias (VTs).
  
  
  RESULTS
  NSVT was documented in 93 patients (32.7%). For HRT assessment, 17 patients (5.6%) were not utilized. Of 282 patients, 68 (24.1%) were HRT positive. During follow-up of 960 ± 444 days, 14 patients (5.0%) reached the end point. NSVT, HRT, and diabetes were significantly associated with the end point. On multivariate analysis, NSVT had the strongest value for the end point, with an HR of 4.4 (95%CI, 1.4-14.3; P = 0.0138). When NSVT combined with HRT, the predictive accuracy is more increased, with an HR of 8.2 (95%CI, 2.9-23.3; P < 0.0001). The predictive values of the combination were higher than single use of NSVT or HRT.
  
  
  CONCLUSIONS
  HRT can facilitate the predictive accuracy of NSVT for identifying patients at risk for serious arrhythmic events in patients with LV dysfunction.
authors: Second Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
authors: Yosuke
authors: Y
authors: Miwa
authors: Hideaki
authors: H
authors: Yoshino
authors: Kyoko
authors: K
authors: Hoshida
authors: Mutsumi
authors: M
authors: Miyakoshi
authors: Takehiro
authors: T
authors: Tsukada
authors: Satoru
authors: S
authors: Yusu
authors: Takanori
authors: T
authors: Ikeda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D015331:Cohort Studies; D016001:Confidence Intervals; D016757:Death, Sudden, Cardiac; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000175:diagnosis