title: Ischemia detection by electrocardiogram in wavelet domain using entropy measure.
abstract: BACKGROUND
  Ischemic heart disease is one of the common fatal diseases in advanced countries. Because signal perturbation in healthy people is less than signal perturbation in patients, entropy measure can be used as an appropriate feature for ischemia detection.
  
  
  METHODS
  Four entropy-based methods comprising of using electrocardiogram (ECG) signal directly, wavelet sub-bands of ECG signals, extracted ST segments and reconstructed signal from time-frequency feature of ST segments in wavelet domain were investigated to distinguish between ECG signal of healthy individuals and patients. We used exercise treadmill test as a gold standard, with a sample of 40 patients who had ischemic signs based on initial diagnosis of medical practitioner.
  
  
  RESULTS
  The suggested technique in wavelet domain resulted in the highest discrepancy between healthy individuals and patients in comparison to other methods. Specificity and sensitivity of this method were 95% and 94% respectively.
  
  
  CONCLUSIONS
  The method based on wavelet sub-bands outperformed the others.
authors.affiliation: Assistant Professor, Biomedical Engineering Department, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Rabbani
authors.forename: Mohammad Parsa
authors.initials: MP
authors.lastname: Mahjoob
authors.forename: Eiman
authors.initials: E
authors.lastname: Farahabadi
authors.forename: Amin
authors.initials: A
authors.lastname: Farahabadi
authors.forename: Alireza Mehri
authors.initials: AM
authors.lastname: Dehnavi