title: Heart Rate Turbulence Is a Powerful Predictor of Cardiac Death and Ventricular Arrhythmias in Postmyocardial Infarction and Heart Failure Patients: A Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  Heart rate turbulence (HRT) has been proposed as a candidate marker of altered autonomic tone, and some studies showed its prognostic value for both cardiac death (CD) and sudden death. Nevertheless, HRT is not currently used in the clinical practice.
  
  
  RESULTS
  We performed a systematic review and meta-analysis of the predictive value of HRT for the end points of total mortality, CD, and fatal and nonfatal ventricular arrhythmias in postacute myocardial infarction and heart failure patients. MEDLINE and The Cochrane Library databases were systematically searched to identify studies, which analyzed the predictive value of abnormal HRT for the defined end points. Twenty studies (25 cohorts: 12 832 patients) were identified by the systematic review, and 15 studies (20 cohorts: 11 499 patients) were included in the meta-analyses. Abnormal HRT was a predictive marker for all the end points in heart failure patients and more markedly in postacute myocardial infarction patients, where 9 out of the 10 cohorts had an ejection fraction >30%. In postacute myocardial infarction patients, HRT had pooled risk ratios of 3.53 (95% confidence interval [CI], 2.54-4.90), 4.82 (95% CI, 3.12-7.45), and 4.48 (95% CI, 3.04-6.60), and positive likelihood ratios of 3.5 (95% CI, 2.6-4.8), 4.1 (95% CI, 3.0-5.7), and 2.7 (95% CI, 2.2-3.3) for total mortality, CD, and arrhythmic events, respectively. The combination of abnormal HRT and T-wave alternans (5 cohorts: 1516 patients) increased the predictive power for CD and arrhythmic events.
  
  
  CONCLUSIONS
  HRT is a powerful predictor of both CD and arrhythmic events, particularly in postacute myocardial infarction patients with ejection fraction >30%. HRT power increases in combination with T-wave alternans analysis.
authors.affiliation: From the Healthcare Research and Innovation Program, PAT-FBK, Trento, Italy (M.D., M.R., G.N.); Department of Cardiology, Santa Chiara Hospital, Trento, Italy (M.D.); and Department of Physics, University of Trento, Italy (M.M., F.R.). disertorim@gmail.com.
authors.forename: Marcello
authors.initials: M
authors.lastname: Disertori
authors.affiliation: From the Healthcare Research and Innovation Program, PAT-FBK, Trento, Italy (M.D., M.R., G.N.); Department of Cardiology, Santa Chiara Hospital, Trento, Italy (M.D.); and Department of Physics, University of Trento, Italy (M.M., F.R.).
authors.forename: Michela
authors.initials: M
authors.lastname: Masè
authors.affiliation: From the Healthcare Research and Innovation Program, PAT-FBK, Trento, Italy (M.D., M.R., G.N.); Department of Cardiology, Santa Chiara Hospital, Trento, Italy (M.D.); and Department of Physics, University of Trento, Italy (M.M., F.R.).
authors.forename: Marta
authors.initials: M
authors.lastname: Rigoni
authors.affiliation: From the Healthcare Research and Innovation Program, PAT-FBK, Trento, Italy (M.D., M.R., G.N.); Department of Cardiology, Santa Chiara Hospital, Trento, Italy (M.D.); and Department of Physics, University of Trento, Italy (M.M., F.R.).
authors.forename: Giandomenico
authors.initials: G
authors.lastname: Nollo
authors.affiliation: From the Healthcare Research and Innovation Program, PAT-FBK, Trento, Italy (M.D., M.R., G.N.); Department of Cardiology, Santa Chiara Hospital, Trento, Italy (M.D.); and Department of Physics, University of Trento, Italy (M.M., F.R.).
authors.forename: Flavia
authors.initials: F
authors.lastname: Ravelli
mesh_terms: D001341:Autonomic Nervous System / Q000503:physiopathology*; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D006333:Heart Failure / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009203:Myocardial Infarction / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D011379:Prognosis; D018570:Risk Assessment; D013318:Stroke Volume; D014693:Ventricular Fibrillation / Q000209:etiology / Q000401:mortality* / Q000503:physiopathology*
keywords: autonomic nervous system; heart failure; implantable cardioverter-defibrillator; myocardial infarction; sudden cardiac death; ventricular tachycardia/fibrillation