Microvolt T-Wave Alternans (MTWA) Clinical Studies

Meta-Analysis of prospective clinical trials that have evaluated microvolt T-wave alternans (MTWA) in populations of patients similar to those studied in MADIT II or SCD-HeFT

Armoundas AA, Hohnloser SH, Ikeda T and Cohen RJ. Can microvolt T-wave alternans testing reduce unnecessary defibrillator implantation? Nature Clinical Practice Cardiovascular Medicine. October 2005; 2:10. The Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) have established that patients with a reduced ejection fraction gain an overall mortality benefit from prophylactic implantable cardioverter-defibrillator therapy. Only a small proportion of the patients in these studies, however, have received life-saving therapy from the defibrillator. Because... [Read More]

Congestive Heart Failure Patients

This study of 549 patients demonstrated that among patients with heart disease and ejection fraction of equal to or less than 40, MTWA can not only identify those patients at high risk but also identify the low-risk patients unlikely to benefit from prophylaxis ICD therapy. (Bloomfield DM, Bigger, JT, Steinman RC, Namerow PB, Parides MK, Curtis AB, Kaufman ES, MD, Davidenko JM, Shinn TS, Fontaine JM. J Am Coll Cardiol, 2006; 47:456-463.)

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.)

MTWA Relative Risk

MTWA abnormal patients are up to 10 times more likely to experience a sudden cardiac event than patients who have a normal MTWA test. 1. Bloomfield DM, Steinman RC, et al. J Am Coll Cardiol, 2006; 47:456-463. 2. Hohnloser SH, Ikeda T, et al. The Lancet. 2003;362:125-126. 3. Ikeda T, Saito H, Tanno K, et al. Am J Cardiol. 2002;89:79-82. 4. Kitamura H, Ohnishi Y, et al. J Am Coll Cardiol. 2002;39:295-300.