title: T-wave alternans predicts mortality in a population undergoing a clinically indicated exercise test.
abstract: OBJECTIVE
  As a part of the Finnish Cardiovascular Study, we tested the hypothesis that T-wave alternans (TWA) predicts mortality in a general population of patients referred for a clinical exercise test.
  
  
  RESULTS
  A total of 1037 consecutive patients (mean age+/-SD of 58+/-13 years, 673 men and 364 women) with a clinically indicated exercise test and with technically successful electrocardiographic (ECG) data during a bicycle ergometer test were included in the study. Digital ECGs were recorded and TWA was analysed continuously with the time-domain modified moving average method. The maximum TWA value at heart rate (HR)<125 b.p.m. was derived and its capacity to stratify risk for all-cause death, cardiovascular death, and sudden cardiac death (SCD) was tested. During a follow-up of 44+/-7 months (mean+/-SD), 59 patients died; 34 were due to cardiovascular causes and 20 were due to SCD. In multivariate analysis after adjustment for age, sex, use of beta-blockers, functional class, maximal HR during exercise, previous myocardial infarction, and other common coronary risk factors, the relative risk of TWA>or=65 microV for SCD was 7.4 (95% CI, 2.8-19.4; P<0.001), for cardiovascular mortality 6.0 (95% CI, 2.8-12.8; P<0.001), and for all-cause mortality 3.3 (95% CI, 1.8-6.3; P=0.001).
  
  
  CONCLUSIONS
  Time-domain TWA analysis powerfully predicts mortality in a general population undergoing a clinical exercise test.
authors.affiliation: Department of Pharmacological Sciences, Medical School, University of Tampere, and Laboratory of Atherosclerosis Genetics, Department of Clinical Chemistry, Tampere University Hospital, Finland.
authors.forename: Tuomo
authors.initials: T
authors.lastname: Nieminen
authors.forename: Terho
authors.initials: T
authors.lastname: Lehtimäki
authors.forename: Jari
authors.initials: J
authors.lastname: Viik
authors.forename: Rami
authors.initials: R
authors.lastname: Lehtinen
authors.forename: Kjell
authors.initials: K
authors.lastname: Nikus
authors.forename: Tiit
authors.initials: T
authors.lastname: Kööbi
authors.forename: Kari
authors.initials: K
authors.lastname: Niemelä
authors.forename: Väinö
authors.initials: V
authors.lastname: Turjanmaa
authors.forename: Willi
authors.initials: W
authors.lastname: Kaiser
authors.forename: Heini
authors.initials: H
authors.lastname: Huhtala
authors.forename: Richard L
authors.initials: RL
authors.lastname: Verrier
authors.forename: Heikki
authors.initials: H
authors.lastname: Huikuri
authors.forename: Mika
authors.initials: M
authors.lastname: Kähönen
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality*; D002318:Cardiovascular Diseases / Q000401:mortality / Q000517:prevention & control; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D004562:Electrocardiography; D005080:Exercise Test / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D012307:Risk Factors