MTWA a Good Predictor of Sudden Cardiac Death

A new study reinforces the value of the Microvolt T-wave Alternans (MTWA) test in identifying patients at risk of sudden cardiac death (SCD).

Researchers from Kyoto University Hospital (Japan) conducted a prospective multicenter study of patients with cardiomyopathy and ejection fraction of 40% or lower, enrolling 453 patients from 38 institutions in Japan. Of these, 280 patients underwent noninvasive MTWA testing using the analytic spectral method. The researchers found that at a median follow-up of 36 months, patients with an abnormal MTWA test were 4.4 times more likely to experience a life-threatening arrhythmia or SCD than those with a normal test. The researchers reported that the three-year negative predictive value was 97%, indicating that patients with a normal or negative MTWA test are at low risk for experiencing sudden death. According to the researchers, this high negative predictive value of the MTWA test can help risk stratify patients who have the lowest risk of SCD, and who are not likely to benefit from ICD therapy. The study was presented by lead author Satoshi Shizuta, M.D., at the American Heart Association (AHA) scientific sessions, held during November 2009 in Orlando (FL, USA).

"The PREVENT-SCD trial further confirms the results of several previously published studies of MTWA in patients with left ventricular dysfunction,” said Ali Haghighi-Mood, Ph.D., president and CEO of Cambridge Heart (Tewksbury, MA, USA), the developers of the MTWA test. "The value of MTWA as an accurate predictor of sudden cardiac arrest in this population has become very well established.”

Microvolt T-Wave Alternans is defined as an alternation in the morphology of the T-wave in an every other beat or AB-AB pattern, and has long been associated with ventricular arrhythmias and sudden death. First recognized nearly a century ago, the microvolt alteration indicates the presence of a type of cellular metabolic activity that frequently leads to tachyarrhythmias. MTWA testing has been approved by the U.S. Food and Drug Administration (FDA).

Related Links:
Kyoto University Hospital
Cambridge Heart