Columbia University Medical Center is reporting in its press release that an NIH-sponsored study looked at the accuracy of Microvolt T-wave Alternans (MTWA) test to stratify patients who are thought to be in need of an implantable cardiac defibrillator (ICD). The results of the study, coordinated by Columbia researchers, were published in the latest issue of the Journal of the American College of Cardiology. According to J. Thomas Bigger, MD, professor of medicine at Columbia University Medical Center, who conducted the research, “… this noninvasive and inexpensive office-based test can identify up to a third of candidates for the devices who are not likely to benefit from them.”
The technology, that was initially developed by MIT with support and funding from NASA’s Johnson Space Center and the National Space Biomedical Research Institute in Houston, Texas, is now marketed as HearTwave® II Microvolt T-Wave Alternans System, by Massachusetts-based Cambridge Heart, Inc.
According to the company:
Microvolt T-Wave Alternans is a beat-to-beat fluctuation in the amplitude of the T-wave at a microvolt level. When detected this indicates the presence of a type of cellular metabolic activity that frequently leads to tachyarrhythmias. Microvolt T-Wave Alternans was cleared by the FDA for its ability to predict ventricular tachyarrhythmias and sudden cardiac death.
With the Microvolt T-Wave Alternans testing, you can stratify your patients’ risk of sudden cardiac death and use the test results as a tool to guide an appropriate care plan based on each individual patient’s risk profile. Highest risk patients (MTWA positive) should be referred for electrophysiology consultation while low risk patients (MTWA negative) can be managed on optimal medical therapy.
At the conclusion of a Microvolt T-Wave Alternans (MTWA) Test, the Alternans Report Classifier generates an individual patient report. This detailed report provides a graphical representation of the magnitude of Microvolt T-Wave Alternans over the duration of the diagnostic session including rest, exercise, and recovery.
The system provides the classification parameters and clinical interpretation and suggests how a determinate test can be obtained if the result is indeterminate.
How the system interprets and classifies the Microvolt T-Wave Alternans test report as positive, negative, or indeterminate requires a determination of whether Microvolt T-Wave Alternans is present, and if it is present, is it sustained or consistently present above the threshold heart rate which is referred to as onset heart rate.
When a test is classified as positive this indicates the presence of sustained alternans below the predetermined threshold heart rate of 110 bpm.
For a test to be negative, this requires that there is a minute above a heart rate of 105 bpm without any significant Microvolt T-Wave Alternans that is free of artifact that could potentially obscure Microvolt T-Wave Alternans.
All other tracings are classified as indeterminate.
To learn about the system, go to the product page at Cambridge Heart…