title: Prognostic value of average T-wave alternans and QT variability for cardiac events in MADIT-II patients.
abstract: BACKGROUND
  Identifying which patients might benefit the most from ICD therapy remains challenging. We hypothesize that increased T-wave alternans (TWA) and QT variability (QTV) provide complementary information for predicting appropriate ICD therapy in patients with previous myocardial infarction and reduced ejection fraction.
  
  
  METHODS
  We analyzed 10-min resting ECGs from MADIT-II patients with baseline heart rate >80 beats/min. TWA indices IAA and IAA90 were computed with the multilead Laplacian Likelihood ratio method. QTV indices QTVN and QTVI were measured using a standard approach. Cox proportional hazard models were adjusted considering appropriate ICD therapy and sudden cardiac death (SCD) as endpoints.
  
  
  RESULTS
  TWA and QTV were measured in 175 patients. Neither QTV nor TWA predicted SCD. Appropriate ICD therapy was predicted by combining IAA90 and QTVN after adjusting for relevant correlates.
  
  
  CONCLUSIONS
  Increased TWA and QTV are independent predictors of appropriate ICD therapy in MADIT-II patients with elevated heart rate at baseline.
authors.affiliation: CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain; Aragón Institute of Engineering Research, IIS Aragón, Universidad de Zaragoza, Zaragoza, Spain. Electronic address: violeta@unizar.es.
authors.forename: Violeta
authors.initials: V
authors.lastname: Monasterio
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Martínez
authors.forename: Pablo
authors.initials: P
authors.lastname: Laguna
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.forename: Slava
authors.initials: S
authors.lastname: Polonsky
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.forename: Mark
authors.initials: M
authors.lastname: Haigney
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Couderc
mesh_terms: D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D003936:Diagnosis, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D015716:Electrocardiography, Ambulatory / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000534:rehabilitation; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000706:statistics & numerical data; D018579:Patient Selection; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Holter ECG; ICD therapy; MADIT-II; Sudden cardiac death; T-wave alternans