Microvolt T wave alternans (MTWA)--a new non-invasive predictor of sudden cardiac death.

Over 10 million people are at high risk of sudden cardiac death (SCD). In order to stratify the risk of SCD due to ventricular tachyarrhythmia, additional methods are required. In the past years, the development of implantable cardioverter/defibrillator (ICD) has become an effective therapeutic option for patients at high risk for SCD, albeit ICD is both expensive and invasive. The Microvolt T-Wave Alternans Test (MTWA, Cambridge Heart Inc.) is a non-invasive method with a stronger positive predictive value in the assessment of arrhythmic risk, when compared to invasive electrophysiological studies (EPS). MTWA has been proved at least an equivalent or even a more sensitive risk predictor of ventricular tachyarrhythmia and/or SCD. MTWA may be considered as a first-line screening test for patients with ventricular arrhythmia history, in order to discriminate the high risk / low risk subgroups, prior to invasive EPS and/or treatment.