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Estimation of low level alternans using periodicity transform - simulation and European ST/T database results

The periodicity transform (PT) provides a computationally efficient approach to detect the presence and estimate the amplitude of low level T wave alternans from surface ECG recordings. The objective of this study was to evaluate the performance of PT in a set of artificially generated alternans episodes and in the European ST (EST) database. The first set of simulations generated a numerical sequence of alternans pattern. The second set generated alternans patterns in identical, simulated beats in random locations. In each beat, T wave peak, T wave area around the peak, and variances of four T wave segments at constant intervals from the R fiducial point were utilized for alternans detection. Application of PT to the above simulations resulted in 100% sensitivity to alternans. Performance of PT under noisy conditions was robust, even at noise-to-signal ratio of -5 dB. Application of PT to ECG records in the EST database detected multiple episodes of T wave alternans. In conclusion, PT provides complimentary information to increase the detection accuracy of T wave alternans in surface ECG.