Session P72.3

Relation between Depolarization and Repolarization Phases in Body Surface QRST Integral Maps

M Fereniec*, G Stix, M Kania, T Mroczka, R Maniewski

Institute of Biocybernetics & Biomedical Engineer.
Warsaw, Poland

The body surface QRST integral maps are considered to reveal primary repolarization changes and are used in assessment of dispersion of repolarization phase in arrhythmia vulnerability diagnosis. The aim of the study was to assess the relations between QRS, ST-T and QRST integral maps in three groups: healthy volunteers, patients after myocardial infarction (MI) and patients with implanted cardioverter-defibrillator (ICD).
The 64 lead HR ECG system was used. The time-averaged signals were analyzed. Two correlation coefficients were calculated in all three groups: between QRS and QRST integral maps and between ST-T and QRST integral maps.
The obtained results showed that the mean correlation coefficient between STT and QRST integral maps was high in the group of healthy subjects (0.88 ±0.1), lower in the group of myocardial infarction patients (0.59±0.54), and lowest in the group of ICD patients (0.38+0.56). In the MI patients lower STT-QRST correlation coefficients were observed in patients with lower LVEF (below 35%). In ICD patients group the correlation coefficients were higher in patients with higher LVEF (over 40%). There was no difference in mean values of correlation coefficients between QRS and QRST integral maps between all groups. However the QRS-QRST correlation was high in patients with low STT–QRST correlation and the spatial pattern of QRST integral maps was determined by QRS integral maps in all those patients.
The QRST integral maps were less correlated to STT integral maps in two studied groups of patients, especially in patients with implanted ICD, in comparison to control group of healthy subjects, where high STT-QRST correlations were observed.
In conclusion, the relation of depolarization phase with repolarization phase and the influence of depolarization sequence on repolarization sequence is noticeably disrupted in patients with impaired systolic function. In such cases the QRST integral maps seems to reflect depolarization-repolarization disorder rather than only repolarization dispersion.

(Abstract Control Number: 103)