Computer Detection of Non-Stationary T Wave Alternans using a New Correlation Method

Detection of microvolt T wave alternans (TWA) is a non-invasive method to identify patients at risk for sudden cardiac death. ECGs show that visible TWA is often nonstationary. Thus, we developed a new correlation method (CM) for TWA detection, and we tested CM's ability to detect non-stationary TWA in comparison with accepted spectral method (SM). In a simulation study CM and SM were used to evaluate stationary and non-stationary TWA of different amplitude. Other simulated conditions included: background noise, poor synchronization and windowing of the T waves; and amplitude respiration modulation of the T wave.