PRECORDIAL QT DISPERSION AND INDUCIBLE VENTRICULAR-TACHYCARDIA

We compared the performance of precordial QT dispersion, late potentia ls on the signal-averaged electrocardiogram (EGG), and reduced left ve ntricular ejection fraction for identification of inducible ventricula r tachycardia (VT) in 162 patients undergoing electrophysiologic study (EPS). QT(apex) dispersion in 56 patients with inducible VT (72 +/- 5 5 msec) was greater than that in 106 patients without inducible VT (55 +/- 36 msec, p < 0.01); dispersion was greater in both groups than in 144 normal subjects (33 +/- 19 msec), A QT(apex) dispersion partition of more than 68 msec, the upper ninety-fifth percentile in normal sub jects, identified inducible VT with a specificity of 75% and a sensiti vity of 45%. Although the performances of late potentials (specificity 82%, sensitivity 59%) and reduced election fraction (specificity 86%, sensitivity 54%) were each stronger than QT dispersion alone for iden tification of inducible VT, abnormal QT(apex), dispersion remained a s ignificant additional predictor of inducible VT in a logistic regressi on model that included the three variables (specificity 78%, sensitivi ty 75%).