ALGEBRAIC DECOMPOSITION OF THE TU WAVE MORPHOLOGY PATTERNS

In principle, the T wave results from the differences in durations of action potentials (AP) of different ventricular regions. Based on this concept, a mathematical model has been developed that represents the TU wave morphology as a summation of four AP-like functions: TU = S1 - S2 + L1 - L2. The sigmoidal shape of AP-like curves is produced by Hi ll's equation V(t) = a . t(n)/(b(n) + t(n)). Each of the decomposition functions is characterized by two parameters: the amplitude at the be ginning of QRS (A(max)), and the duration at 5% of A(max) (D-95). The set of four decomposition functions leads to eight parameters that pro vide detailed characteristics of the TU wave morphology. The model was validated using 170 TU wave complexes recorded digitally in leads V-2 -V-6 from 22 normal subjects and 12 patients with abnormal TU wave mor phologies (negative, biphasic, and notched T waves). The electrocardio graphic signals were sampled at 100 Hz and a best-fit procedure was us ed to obtain the decomposition. In all cases the coefficients of corre lation between original TU patterns and their mathematical models were greater than or equal to 0.99. The mean absolute difference between t he observed and modeled values of the TU patterns was similar in cases with normal and abnormal TU wave morphologies (4.65 +/- 0.41 mu V vs 5.19 +/- 0.48 mu V, respectively) demonstrating that the model is capa ble of describing and categorizing various TU patterns by a set of eig ht numerical parameters.