Microvolt T-Wave Alternans™ (MTWA)
Clinical Studies

MTWA Clinical Trials

View a summary of the results of four major clinical trials of MTWA. Combined, these trials enrolled over 2,800 subjects including patients with left ventricular dysfunction (Bloomfield, Chow, ALPHA) as well as those with preserved EF (Ikeda).

PREVENT-SCD Study – Presented at AHA 2009

PREVENT-SCD a prospective multi-center study of patients with cardiomyopathy and ejection fraction of 40% or lower, enrolled a total of 453 patients from 38 institutions in Japan. "MTWA has a very high negative predictive value for lethal arrhythmias in this population,” said Dr. Satoshi Shizuta, lead author of the study.

Risk Factors of SCD – Supplement to March Issue of Heart Rhythm

This includes the publication of five articles supporting the use of Microvolt T-Wave Alternans (MTWA) testing. Featured in the supplement is a comprehensive meta-analysis of 6,000 patients confirming the value of MTWA as a non-invasive marker of risk for sudden cardiac arrest (SCA).

Congestive Heart Failure Patients

In the prospective study of 282 non-ischemic patients, MTWA testing was negative in 34%, and not negative in 66%. In patients with NIDCM, a negative MTWA test predicts a high 2-year event free survival. ICD prophylaxis in these patients may not be needed. (Costantini O, et al. AHA 2004 Oral Presentation)

This prospective study of 107 consecutive patients compared MTWA predictive accuracy to other non-invasive risk stratifiers in a CHF population. The results indicate only MTWA as a significant and independent predictor of SCD with a negative predictive value of 100%. (Klingenheben, Zabel, D'Agostino, Cohen, Hohnloser. Lancet. 2000;356:651-652.)

MADIT II Type Patients

This study of 177 patients demonstrated that an abnormal MTWA test is a strong predictor of death in patients with ischemic heart disease and left ventricular dysfunction that fit MADIT II criteria. It also demonstrated that MTWA is effective at identifying a group of patients not likely to benefit from ICD therapy. (Bloomfield, Steinman, et al. Circulation. 2004; 110:1885-89.)

Post MI Patients

This prospective study of 850 consecutive patients compared the MTWA predictive accuracy to EF and SAECG in the acute MI population. The study indicated that MTWA had the highest predictive accuracy compared to other non-invasive risk stratifiers. The findings also indicates an extremely low event rate of 1% among MTWA negative patients. (Ikeda, Saito, Tanno, Shimizu, Watanabe, Ohnishi, Kasamaki, Ozawa. AJC. 2002;89:79-82.)

Non-Ischemic DCM

This 137-patient study evaluated the ability of MTWA and other risk stratifiers to identify patients with DCM who are at risk of ventricular tachyarrhythmic events. The findings indicate that MTWA is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM. (Hohnloser, Klingenheben, Bloomfield, Dabbous, Cohen. JACC. 2003;41:2220-2224.)

EP Study vs. MTWA

This multicenter prospective trial examined 313 patients in sinus rhythm who were undergoing an EP Study. The study results indicate, that in comparing MTWA predictive accuracy to EPS, the two have comparable positive predictive values while the MTWA presents a significantly higher negative predictive value. (Gold, Bloomfield, Anderson, El-Sherif, Wilber, Groh, Estes, Kaufman, Greenberg, Rosenbaum. JACC. 2000;36:2247-2253.)