title: QT and JT dispersion in patients with monomorphic or polymorphic ventricular tachycardia/ventricular fibrillation.
abstract: The present study evaluates the repolarization abnormalities in patients with monomorphic sustained ventricular tachycardia (MVT) and polymorphic ventricular tachycardia/ventricular fibrillation (PMVT/VF) by measuring QT and JT dispersion on the surface electrocardiogram (ECG). QT dispersion is a predictor of ventricular arrhythmias in several clinical settings. However, the value of QT and JT dispersion in identifying patients at risk for PMVT/VF is controversial. Maximum QT (JT) interval duration and QT (JT) dispersion were compared between 20 healthy individuals, 12 patients with inducible MVT during programmed electrical stimulation and seven patients with PMVT/VF recorded during 24-hour ambulatory ECG or induced by programmed electrical stimulation. QT dispersion was 40 +/- 9 ms in the control group, 63 +/- 21 ms in the MVT group, and 79 +/- 31 ms in the PMVT/VF group. QT dispersion in both the MVT and PMVT/VF groups were significantly greater than in the control group (P <.001 and P <.0001, respectively); however, there was no significant difference between the MVT and PMVT/VF groups. JT dispersion was 41 +/- 14 ms in the control group, 69 +/- 14 ms in the MVT group and 103 +/- 37 ms in the PMVT/VF group. JT dispersion differed significantly between the study groups and was significantly increased in PMVT/VF group than in the control group or MVT groups (P <.0001 vs. the control group, P <.005 vs. the MVT group). Patients with PMVT/VF have a greater dispersion of ventricular repolarization time. Repolarization abnormalities are important for ventricular arrhythmogenesis and detectable on the surface ECG.
authors.affiliation: Department of Internal Medicine, Kobe University School of Medicine, Kobe, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shimizu
authors.forename: Y
authors.initials: Y
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*