title: Evaluation of the T-wave alternans detection methods: a simulation study.
abstract: OBJECTIVE
  The aim of this study was to evaluate influence of noise, T-wave jitter and electrocardiographic (ECG) signal parameters on sensitivity of T-wave alternans (TWA) detection methods.
  
  
  METHODS
  Methods of the TWA detection were tested: correlation (CM), spectral (FFTM), spectral with coherent averaging (CFFTM), complex demodulation (CDM), Karhunen-Loeve transform (KLT) and KLT realized by adaptive filtering. The TWA amplitude and duration time were estimated on simulated ECG signals. Gaussian and physiological noises at different level were added. Influence of sampling frequency and amplitude resolution of the ECG signal was tested. Detection sensitivity was calculated.
  
  
  RESULTS
  The TWA episodes in presence of white noise with signal to noise ratio (SNR) greater then 15 dB were reliably detected. For signals with high noise level better sensitivity was received with the CM. For the spectral methods, the best parameters were obtained with the CFFTM but for physiological noises all the methods were unable to detect the TWA episodes when SNR was lower then 10 dB. Analysis done using the CM and the CDM strongly depended on sampling frequency if the TWA episodes were short and had low amplitude.
  
  
  CONCLUSIONS
  All spectral methods are sensitive to physiological interference. Changes of the sampling frequency should be very carefully applied.
authors.affiliation: Institute of Biocybernetics and Biomedical Engineering PAS, Warsaw, Poland. djanusek@ibib.waw.pl
authors.forename: Dariusz
authors.initials: D
authors.lastname: Janusek
authors.forename: Zdzislaw
authors.initials: Z
authors.lastname: Pawlowski
authors.forename: Roman
authors.initials: R
authors.lastname: Maniewski
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000503:physiopathology; D003198:Computer Simulation; D004562:Electrocardiography; D006801:Humans; D011237:Predictive Value of Tests; D012815:Signal Processing, Computer-Assisted