JT DISPERSION IN WOLFF-PARKINSON-WHITE-SYNDROME - EFFECT OF ECCENTRICVENTRICULAR DEPOLARIZATION ON THE DISPERSION OF REPOLARIZATION

There is much interest in QT dispersion for noninvasive risk stratific ation of patients at risk of arrhythmias. However, little is known abo ut the genesis of abnormal QT dispersion. In particular, whether eccen tric ventricular depolarization, as seen in preexcitation, can lead to abnormal dispersion of repolarization is unknown. We studied 24 child ren aged 1-19 years (mean +/- SD, 11 +/- 5 years) with manifest preexc itation due to Wolff-Parkinson-White syndrome who had successful cathe ter ablation. Standard ECGs done preablation, early postablation (<1 w eek), mid postablation (>1 week, <2 months), and late postablation (>2 months) were reviewed. The QRS duration prior to ablation ranged from 90-160 ms (mean +/- SD, 123 +/- 21 ms). On the preablation EGG, the J T and JTc dispersions showed no relationship to the QRS duration (r = 0.04 and 0.07, respectively). There was no change in JT dispersion whe n the preablation (42 +/- 15 ms) ECG was compared to early (43 +/- 15 ms), mid (44 +/- 13 ms), and late postablation (48 +/- 19 ms) ECGs. Th ere rr as no significant change in JTc dispersion as well. Thus, JT di spersion is unrelated to QRS duration and unaffected by catheter ablat ion in patients with Wolff-Parkinson-White syndrome. Eccentric ventric ular depolarization does not lead to abnormal dispersion of repolariza tion.