AHA: Microvolt T-wave Alternans test for SCD gets boost

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A multicenter study from Japan found that performing a microvolt T-wave alternans test on patients with left ventricular dysfunction accurately predicts whether patients have a risk for sudden cardiac death.

The PREVENT-SCD (PRospective EValuation of VENtricular Tachyarrhythmic Events and Sudden Cardiac Death in Patients with Left Ventricular Dysfunction) trial results were presented at the recent American Heart Association meeting in Orlando, Fla.

Satoshi Shizuta, MD, from Kyoto University Hospital, and colleagues enrolled 453 patients with cardiomyopathy and an ejection fraction of 40 percent or lower from 38 institutions in Japan.

A total of 280 patients underwent non-invasive microvolt T-wave alternans (MTWA) testing using the analytic spectral method and were followed for up to three years.

MTWA 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 testing is cleared by the FDA for its ability to predict ventricular tachyarrhythmias and sudden cardiac death.

In the study 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.

Researchers found the three-year negative predictive value to be 97 percent, indicating that patients with a normal or negative MTWA test are at low risk for experiencing sudden death.

“MTWA has a very high negative predictive value for lethal arrhythmias in this population,” said Shizuta.

In PREVENT-SCD, 29 percent of patients eligible for the test had a negative MTWA result. The researchers said that these patients are at very low risk for SCD in the next three years.

Shizuta said that the PREVENT-SCD trial further confirms results of several previously published studies of MTWA in patients with left ventricular dysfunction. The high negative predictive value of the MTWA test can help risk stratify patients who have the lowest risk of SCD and are not likely to benefit from ICD therapy.