Precordial QT dispersion and inducible ventricular tachycardia☆☆☆★★★

Abstract 

We compared the performance of precordial QT dispersion, late potentials on the signal-averaged electrocardiogram (ECG), and reduced left ventricular ejection fraction for identification of inducible ventricular tachycardia (VT) in 162 patients undergoing electrophysiologic study (EPS). QT_apex dispersion in 56 patients with inducible VT (72 ± 55 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 subjects, identified inducible VT with a specificity of 75% and a sensitivity of 45%. Although the performances of late potentials (specificity 82%, sensitivity 59%) and reduced ejection fraction (specificity 86%, sensitivity 54%) were each stronger than QT dispersion alone for identification of inducible VT, abnormal QT_apex dispersion remained a significant additional predictor of inducible VT in a logistic regression model that included the three variables (specificity 78%, sensitivity 75%). (Am Heart J 1997;134:1005-13.)