NEW INSIGHT INTO REPOLARIZATION ABNORMALITIES IN PATIENTS WITH CONGENITAL LONG QT SYNDROME - THE INCREASED TRANSMURAL DISPERSION OF REPOLARIZATION

There is evidence from experimental studies that the time interval fro m the peak to the end of T-wave reflects the transmural dispersion in repolarization (electrical gradient) between myocardial ''layers'' (ep icardial, M-cells, endocardial). Since Congenital Long QT Syndrome (LQ TS) is considered to be classical disease or repolarisation abnormalit ies, we performed the present study to assess the transmural dispersio n of repolarization in LOTS patients. The study group consisted of 17 patients: 7 LQTS and 10 pts from the control group. In each patient th e 24-hour ECG recording was performed on magnetic tape. The interval f rom the peak to the end of the T-wave (TpTo),vas automatically measure d by Holter system during every hour as a measure of transmural disper sion of repolarisation. Thereafter the mean TpTo from 24-hours was cal culated Irt addition the spatial QT dispersion was measured from 12 le ad ECG and 3 channel Holter tape as a difference between the shortest and the longest QT interval between leads. The values were compared be tween groups using the Anova test. TpTo was 79,6+/-9,6 ms (72-92 ms) i n LOTS group and 62,4+/-7,5 ms (51-70) in the control group (p<0.001). In LQTS group TpTo was significantly longer at night hours 72,5+/-2 w hen compared to day hours 87,4+/-8 (p<0.01). The spatial QT dispersion was significantly higher in LOTS patients when compared to control bo th in It-lend standard and Holter EGG. Congenital long QT syndrome is associated with increase in both transmural and spatial dispersion of repolarization. The extent of prolongation of the terminal portion? of QT in patients with congenital long Qr syndrome is greater at night s leep hours compared to daily activity.