Microvolt T-Wave
Alternans Test Accurately Predicts Risk of Sudden
Cardiac Arrest, Meta-Analysis Finds
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Evidence from 13 clinical studies involving 6,000
heart patients and four additional papers published today support MTWA
testing
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The meta-analysis,
conducted by a group led by Stefan Hohnloser, MD,
FHRS, of the JW Goethe University Division of Cardiology in Frankfurt, Germany,
assessed 13 MTWA clinical studies involving approximately 6,000 cardiac
patients.
“The results
demonstrate that MTWA testing is a consistently accurate predictor of sudden
cardiac death and cardiac arrest in patients who do not already have
implantable cardiac defibrillators (ICDs),” said Dr. Stefan Hohnloser.
“These are the patients for whom MTWA testing is intended."
The meta-analysis
authors also conclude that:
- Patients who test
negative for MTWA abnormalities are at extremely low risk (0.3%) for SCA
in the next 12 months if ICD is not implanted.
- MTWA testing can help
doctors guide ICD therapy to appropriate patients and overcome the
widespread reluctance of patients and referring physicians to accept ICD
therapy.
- In clinical trials,
appropriate ICD shocks are an unreliable surrogate endpoint for SCA and
can skew results of risk stratification studies.
The Heart Rhythm supplement
also includes:
- A second meta-analysis of
MTWA testing in patients with non-ischemic heart disease, authored by Gaetano De Ferrari, MD and Antonio Sanzo,
MD of the Department of Cardiology at Fondazione
IRCCS Policlinico San Matteo,
Pavia Italy. Analyzing eight available trials involving 1,450 patients,
the paper indicates that in this population negative MTWA results can help
patients and their physicians decide whether ICD therapy may safely be
avoided.
- An article by Michael J. Mirro, MD, Medical Director of the Parkview Health
System Clinical Research Center in Fort Wayne Indiana, who describes how
his center has incorporated MTWA testing into clinical practice to
complement other methods for identifying and educating patients about the
risk of SCA.
- A review of numerous
studies concerning the underlying cellular mechanisms of T-wave alternans. The authors conclude that microvolt T-wave alternans is a marker of cellular changes that make
the heart susceptible to sudden cardiac arrest. The review was carried out
by Michael Cutler, DO, PhD, and David S. Rosenbaum, MD, of the Heart and
Vascular Research Center at the Department of Biomedical Engineering at
Case Western Reserve University in Cleveland.
- A review by Navinder Sawhney, MD and Sanjiv Narayan, MD of the
University of California at San Diego that underscores the value of MTWA
testing in patients who have had heart attacks but do not fall within
current guidelines for ICD implantation.