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Evaluation of two methods for segmentation width Onda T ECG

Abstract:

In this work, two methods for T wave segmentations were compared: classic method based on differentiator filter and the method based on slope estimation. This study was carried out on simulated electrocardiogram (ECG) signals with four simulated added noise types: (a) baseline wander due to breathing (0-0.5 Hz), (b) motion artifacts (3-5 Hz), (c) electromyography and motion artifacts (Gaussian white noise), (c) mixed effects (sum of the previous noises). Four conditions of Signal to Noise Ratio (SNR) were computed: 5, 10, 15, 20 and 25 dB. The beginning, the end and the width of the T wave was determined with both methods and the mean absolute error was computed for all signals. The slope estimation method shows a T wave width larger than the obtained with the differentiator filter. Both methods showed that the end location is easier to find than the beginning of the T wave. The achieved performance shows a satisfying behavior of both methods in favorable conditions of SNR. However, the differentiator filter method shows better performance that the method base on slope estimation. The noise due to motion artifacts affect greatly the mean absolute error in the beginning and end location of the T wave. An important increase of T wave width variability induced by the artifacts was observed. © Springer-Verlag Berlin Heidelberg 2007.