Notice of Violation of IEEE Publication Principles: A polycoherence-based ECG signal non-linearity detector

Notice of Violation of IEEE Publication Principles

"A Polycoherence-Based ECG Signal Non-Linearity Detector"
by Walid A. Zgallai,
in the 17th International Conference on Digital Signal Processing (DSP), July 2011

After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles.

This paper contains substantial duplication of original text from the paper cited below. The original text was copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission.

Due to the nature of this violation, reasonable effort should be made to remove all past references to this paper, and future references should be made to the following article:

"Application of Higher-order Statistics and Subspace Based Techniques to the Analysis and Diagnosis of Electrocardiogram Signals,"

by Sahar El-Khafif,
PhD thesis, School of Engineering, City University, UK, 2002


This paper proposes a new algorithm to detect non-linearities in ECG signals and to determine the order of non-linearity. The ECG bispectrum is analysed and the bicoherence index is calculated to identify non-linearity. The diagonal slice of the polycoherence index of any order, calculated using the diagonal slice of the polyspectrum of the same order and the power spectrum, is proposed as an estimator. The possibility of higher-order non-linearities in ECG signals is investigated using these slices. Physiological and pathological cases have been studied. The analysis of the bispectrum and bicoherence index reveals tight quadratic interactions among frequencies in the region (0-20 Hz), which suggests the existence of non-linearities. The polyspectrum and polycoherence slices indicate the presence of higher-order phase-coupled harmonics, in the physiological cases, which is attributed to higher order non-linearities. Differences between physiological and pathological cases are assessed and a decrease in the non-linearity order could be correlated with pathological conditions.