Microvolt T-wave alternans for the risk stratification of ventricular tachyarrhythmic events: a meta-analysis.
OBJECTIVE
The objective of this study was to perform a meta-analysis of the predictive value of microvolt T-wave alternans (MTWA) testing for arrhythmic events in a wide variety of populations.


BACKGROUND
Previous studies describing the use of MTWA as a predictor of ventricular tachyarrhythmic events have been limited by small sample sizes and disparate populations.


METHODS
Prospective studies of the predictive value of exercise-induced MTWA published between January 1990 and December 2004 were retrieved. Data from each article were abstracted independently by two authors using a standardized protocol. Summary estimates of the predictive value of MTWA were made using a random-effects model.


RESULTS
Data were accumulated from 19 studies (2,608 subjects) across a wide range of populations. Overall, the positive predictive value of MTWA for arrhythmic events was 19.3% at an average of 21 months' follow-up (95% confidence interval [CI] 17.7% to 21.0%), the negative predictive value was 97.2% (95% CI 96.5% to 97.9%), and the univariate relative risk of an arrhythmic event was 3.77 (95% CI 2.39 to 5.95). There was no difference in predictive value between ischemic and nonischemic heart failure subgroups. The positive predictive value varied depending on the population of patients studied (p < 0.0001).


CONCLUSIONS
Microvolt T-wave alternans testing has significant value for the prediction of ventricular tachyarrhythmic events; however, there are significant limitations to its use. The predictive value of MTWA varies significantly depending on the population studied. Careful standardization is needed for what constitutes abnormal MTWA. The incremental prognostic value of MTWA when used with other methods of risk stratification is unclear.
Gehi
Anil K
AK
Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York 10029, USA. anil.gehi@msnyuhealth.org
Stein
Russell H
RH
Metz
Louise D
LD
Gomes
J Anthony
JA
D000328:Adult; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D018570:Risk Assessment; D017180:Tachycardia, Ventricular / Q000209:etiology*