Orini, M;
Hanson, B;
Monasterio, V;
Martinez Cortes, JP;
Hayward, M;
Taggart, P;
Lambiase, P;
(2014)
Comparative Evaluation of Methodologies for T-wave Alternans Mapping in Electrograms.
IEEE Trans Biomed Eng
, 61
(2)
308 -316.
10.1109/TBME.2013.2289304.
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Abstract
Electrograms (EGM) recorded from the surface of the myocardium are becoming more and more accessible. T-wave alternans (TWA) is associated with increased vulnerability to ventricular tachycardia/fibrillation and it occurs before the onset of ventricular arrhythmias. Thus, accurate methodologies for time-varying alternans estimation/detection in EGM are needed. In this paper, we perform a simulation study based on epicardial EGM recorded in vivo in humans to compare the accuracy of four methodologies: the spectral method (SM), modified moving average method (MMA), laplacian likelihood ratio method (LLR) and a novel method based on time-frequency distributions (TFD). A variety of effects are considered, which include the presence of wide band noise, respiration and impulse artifacts. We found that (a) EGM-TWA can be detected accurately when the standard deviation of wide band noise is equal or smaller than 10 times the magnitude of EGM-TWA. (b) Respiration can be critical for EGM-TWA analysis, even at typical respiratory rates. (c) Impulse noise strongly reduces the accuracy of all methods, except LLR. (d) If depolarization time is used as a fiducial point, the localization of the T-wave is not critical for the accuracy of EGMTWA detection. (e) According to this study, all methodologies provided accurate EGM-TWA detection/quantification in ideal conditions, while LLR was the most robust, providing better detection-rates in noisy conditions. Application on epicardial mapping of the in-vivo human heart shows that EGM-TWA has heterogeneous spatio-temporal distribution.
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