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Microvolt T-wave alternans as a predictor of mortality and severe arrhythmias in patients with left-ventricular

Charlotte J van der Avoort1, Kristian B Filion, Nandini Dendukuri

  • 1Department of Medicine, McGill University Health Center, Montreal, Quebec, Canada. charlotte.vanderavoort@gmail.com

BMC Cardiovascular Disorders
|January 30, 2009
PubMed

Insights

Microvolt T-wave alternans (MTWA) can help identify patients with severe left ventricular dysfunction at higher risk for mortality or arrhythmias. Further research is needed to fully define its clinical utility in guiding implantable cardioverter defibrillator decisions.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Diagnostics

Background:

  • Implantable cardioverter defibrillators (ICDs) are effective for primary prevention of arrhythmic events.
  • High costs necessitate identifying patients who benefit most from ICDs.
  • Microvolt T-wave alternans (MTWA) is a potential tool for patient stratification.

Purpose of the Study:

  • To evaluate MTWA as a predictor of mortality and severe arrhythmic events in patients with severe left-ventricular dysfunction.
  • To synthesize evidence from randomized controlled trials and prospective cohort studies.

Main Methods:

  • Systematic literature search of multiple databases (MEDLINE, EMBASE, etc.) from January 1990 to May 2007.
  • Inclusion of primary prevention randomized controlled trials and prospective cohort studies with ≥12 months follow-up.
  • Bayesian hierarchical models used for data synthesis.

Main Results:

  • Analysis of 8 cohort studies with 1,946 patients; no trials identified.
  • Positive MTWA test results were associated with a higher risk of mortality or severe arrhythmic events (RR = 2.7, 95% CrI = 1.4, 6.1).
  • Similar findings observed when comparing non-negative MTWA results to negative results.

Conclusions:

  • A positive MTWA test predicts adverse outcomes in severe left ventricular dysfunction.
  • The clinical utility of MTWA is incompletely defined due to a wide credible interval.
  • High-quality studies are needed to refine MTWA's role in ICD implantation decisions.
Abstract

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