Cardiac Science (Bothell, WA) is making available the Microvolt T-Wave Alternans (MTWA) module for its Quinton Q-Stress cardiac stress test system. The optional package was developed by Cambridge Heart (Tewksbury, MA). As some of you might remember from our previous coverage of this technology, the Microvolt T-wave Alternans stress test looks at beat-to-beat variability in the amplitude of the T-wave at a microvolt level. The technology was initially developed by MIT with support from NASA’s Johnson Space Center and the National Space Biomedical Research Institute in Houston, Texas. The MTWA technology has shown promise in a number of studies by predicting increased patient risk to develop life threatening ventricular arrhythmias or sudden cardiac arrest.
From Cambridge Heart MTWA technology page:
The appearance of Microvolt T-Wave Alternans indicates the presence of a type of cellular metabolic activity that frequently leads to ventricular tachyarrhythmias.
In most situations, the test takes less than 30 minutes to perform. Following the placement of fourteen sensors – 7 Micro-V Alternans Sensors and 7 standard electrodes – in the Frank-lead configuration, the electrodes are connected to the digital ECG amplifier that leads back to the Microvolt T-Wave Alternans enabled system. At the beginning of the test, the patient is directed to begin walking on a treadmill to raise the heart rate. Patients who are unable to exercise can have their heart rates elevated pharmacologically to achieve the higher rate needed for a successful test.
The sub-maximal exercise portion of the test will be approximately 8-10 minutes. Information will be collected for the Microvolt T-Wave Alternans Test while at rest, during exercise and at rest again. Upon test completion, the system analyzes the data and provides the Alternans Report Classification, which is an automatic interpretation of the test results. The test is classified as positive, negative or indeterminate.
Press release: Cardiac Science Introduces MTWA Module for Stress Testing…
Product pages: Microvolt T-Wave Alternans; Quinton Q-Stress cardiac stress testing system
Flashbacks: Will Microvolt T-Wave Alternans Be Incorporated Into Other Devices?; HearTwave® II Microvolt T-Wave Alternans System; Microvolt T-Wave Alternans Testing Shows Promise for Predicting Sudden Cardiac Death