title: Noninvasive identification of two lesions with local repolarization changes using two dipoles in inverse solution simulation study.
abstract: BACKGROUND
  The method for inverse localization and identification of two distinct simultaneous lesions with changed repolarization in the ventricular myocardium (two-vessel disease) is proposed and its robustness to errors in input data is tested in this simulation study.
  
  
  METHODS
  The inverse solution was obtained from the difference between STT integral body surface potential map computed with repolarization changes and the STT integral map from normal activation. In a numerical model of ventricles 48 cases of two simultaneous lesions and 48 cases of a single lesion were modeled. The effect of the lesions was taken to be represented by two dipoles. The input data were disturbed by three types of added noise. Twenty three characteristics of every obtained inverse solution were defined and four of them were used as the features in discriminant analysis task distinguishing the correct inverse solutions identifying two lesions.
  
  
  RESULTS
  The mean localization error for identified two lesions was 1.1±0.7cm. The sensitivity and specificity of quadratic discriminant analysis with cross-validation and feature selection was higher than 90%.
  
  
  CONCLUSIONS
  The combination of the inverse solution with two dipoles and discriminant analysis allows the identification of two simultaneous lesions without a priori information about the number of lesions.
authors.affiliation: Institute of Measurement Science SAS, Bratislava, Slovakia. Electronic address: jana.svehlikova@savba.sk.
authors.forename: Jana
authors.initials: J
authors.lastname: Svehlikova
authors.affiliation: Institute of Measurement Science SAS, Bratislava, Slovakia.
authors.forename: Michal
authors.initials: M
authors.lastname: Teplan
authors.affiliation: Institute of Measurement Science SAS, Bratislava, Slovakia.
authors.forename: Milan
authors.initials: M
authors.lastname: Tysler
mesh_terms: D018780:Body Surface Potential Mapping / Q000379:methods*; D006321:Heart / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted
keywords: Classification of obtained results; Heart model; Inverse solution; Simulation of integral body surface potential maps; Two lesions with changed repolarization