How to do exercise-induced T-wave alternans testing using the spectral method

The present review summarizes current aspects on how to perform noninvasive microvolt T-wave alternans (mTWA) testing in clinical practice. The focus is on methodologic issues such as patient-related, or technical aspects, and interpretation of the results. Special attention is given to the different sources of noise that may interfere with mTWA assessment. The role of beta-blocker therapy and its potential effect on mTWA is discussed as well. In the first clinical studies of mTWA, a high rate of indeterminate test results was observed. In this respect, patient-related indeterminacy has been demonstrated to be associated with an increased mortality and such tests are thus regarded as “abnormal” whereas technically inadequate tests are classified as indeterminate. Since mTWA evolves over time in patients with structural heart disease, the “optimal timing” for mTWA assessment is rather in the chronic phase than in the acute setting of heart disease. (Cardiol J 2008; 15: 288-292