Role of T wave dipolar and nondipolar components in the T wave residuum

BIAGETTI, MARCELO. ARINI, PEDRO. VALVERDE, ESTEBAN. BERTRÁN, GUILLERMO. QUINTEIRO, RICARDO

Sydney, Australia

Congreso; XIV World Congress of Cardiology; 2003

World Heart Federation

It has recently proposed that T wave residuum (TWR, proportion of nondipolar components to the total energy of the T wave) represents more accuralety regional heterogeneity of repolarization than interlead variability of QT interval or QT dispersion. We analyzed the T wave morphology under conditions of increased dispersion in an isolated rabbit heart model in order to determinate the role that play both the dipolar and nondipolar components to account for changes in the TWR.Singular value decomposition was applied to the repolarization signals obtained from 5x8 array multielectrode recording system during premature beats and after d-sotalol (N=9) exposure. Data are expressed as Mean ± SEM of the percentage of change respect to control. We found that both the dipolar and nondipolar components increased significatively during premature beats (134.0± 32.92 % and 63.65 ± 22.36 % for dipolar and nondipolar components respectively, p<0.05) or after d-sotalol exposure (356.730± 203.28 % and 484.55 ± 271.89 % for dipolar and nondipolar components respectively, p<0.05). However, and due to the relative changes observed in the dipolar and nondipokar components, the TWR decreased significatively durin premature beats (-23.06± 11.23 %, p<0.05) and did not exhibited significant changes after d-sotalol exposure.We conclude that TWR accurately reflects an increase in regional heterogeneity of repolarization only when dipolar components of the T wave do not change or increase in a significatively less amount than do nondipoar components.