title: Ambulatory ECG-based T-wave alternans and heart rate turbulence predict high risk of arrhythmic events in patients with old myocardial infarction.
abstract: BACKGROUND
  Few studies have explored risk stratification of arrhythmic events in patients with ischemic heart diseases according to T-wave alternans (TWA) using modified moving average (MMA) method and heart rate turbulence (HRT).
  
  
  RESULTS
  A retrospective analysis of 63 patients who underwent MMA-based TWA and HRT divided the patients into 3 groups: group-C of 21 controls, group-O of 21 patients with old myocardial infarction (OMI) showing no episodes of sustained ventricular tachyarrhythmia (SVT), and group-V of 21 OMI patients with episodes of SVT who received an implantable cardioverter-defibrillator. Among the 3 groups, positive TWA (>or=65 microV) and impaired HRT were observed most frequently in group-V (P<0.05). Using a logistic regression model, TWA yielded an odds ratio of 4.9 (95% confidence interval: 1.2-19.6, P<0.05), which was the only significant covariate for the incidence of life-threatening ventricular arrhythmias during a mean follow-up of 72 months.
  
  
  CONCLUSIONS
  Patients with OMI showing episodes of SVT have a high risk for cardiac death because of abnormal repolarization and autonomic regulation. The analysis of MMA-based TWA and HRT can be a useful tool for predicting OMI patients at high risk of arrhythmic events.
authors.affiliation: Department of Cardiology, Yokohama-Minami Kyosai Hospital, Yokohama, Japan. s-maeda@ja2.so-net.ne.jp
authors.forename: Shingo
authors.initials: S
authors.lastname: Maeda
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nishizaki
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Yamawake
authors.forename: Takashi
authors.initials: T
authors.lastname: Ashikaga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimada
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Asano
authors.forename: Kensuke
authors.initials: K
authors.lastname: Ihara
authors.forename: Tadashi
authors.initials: T
authors.lastname: Murai
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujii
authors.forename: Harumizu
authors.initials: H
authors.lastname: Sakurada
authors.forename: Masayasu
authors.initials: M
authors.lastname: Hiraoka
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control; D017147:Defibrillators, Implantable; D015716:Electrocardiography, Ambulatory; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D016017:Odds Ratio; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy