Abstract : New statistical and spectral detectors, the modified matched pairs t-test, the extended spectral method and the modified spectral method, was proposed for T-wave alternans (TWA) detection gaining robustness according to trend and single frequency interferences. They were compared to classic detectors such as matched pairs t-test, unpaired t-test, spectral method, generalized likelihood ratio test and estimated TWA amplitude within a simulation framework and applied to real data. The optimal detection threshold was selected by using a full Monte-Carlo simulation where signals, with and without alternans episodes, were corrupted by Gaussian noise with different power and single frequency interferences with different tones. All the combinations of noise and frequency were selected and repeated 500 times in order to compute probability of detection (Pd) and the false alarm probability (Pfa), providing ROC curves.
The study group consisted of 50 patients with implantable cardioverter-defibrillator (age: 55.3 +-16.4; LVEF: 42.8 +-15.5), who were paced (ventricular pacing) at 100 bpm. Two-minute recordings were analyzed. The XYZ orthogonal lead system was used. The best performance was reached by using the modified matched pairs t-test (in comparison with the spectral method and other reference methods).