AN EFFECTIVE METHODS TO DEFINE THE SPATIAL DISPERSION USED IN REPRESENTING THE HETEROGENEITY IN VENTRICULAR REPOLARIZATION

An effective method to define the spatial dispersion used to represent the ischemia induced heterogeneity in ventricular repolarization is investigated. The algorithm based on wavelet transformation is adopted to analyze QT and ARI from a 64-channel epicardial ECG data of an ischemic sheep. The quadratic spline wavelet is used to extract QRS with 2 1 scale and T wave with 2 5 scale, and then Q, T, A and R points are determined by definition. The epicardial QT and ARI dispersions are calculated with three methods: extremum difference (ED), standard deviation (SD) and coefficient of variation (CV). It is found that there is no significant difference in QT dispersion before and during ischemia regardless of the dispersion method with CV method having the largest P value. Meanwhile ARI dispersion on the epicardium is significantly increased during ischemia with P CV being the minimum. Furthermore, although the three methods are effective in representing the spatial dispersion, the CV method has a statistical advantage.