Dispersion of QT Interval following Ventricular Premature Beats and Mortality after Myocardial Infarction

Abstract

In a group of 193 postinfarction patients with ventricular premature beats on a resting 12-lead ECG, the dispersion of QT and JT intervals was calculated as a difference between maximum and minimum QT and JT intervals in ventricular premature beats. During a follow-up of 38 ± 17 months, death from all causes was noted in 56 patients. Univariate predictors of mortality included QT dispersion ≥100 ms, JT dispersion ≥100 ms, left ventricular ejection fraction <40%, complete bundle branch block, ‘R-on-T’ index of ventricular premature beats <1 and age of patients >60 years. At multivariate Cox proportional hazards survival analysis, only QT dispersion ≥100 ms, left ventricular ejection fraction <40% and complete bundle branch block had an independent relation to postinfarction mortality. The final model selected increased QT dispersion as the prognostic factor which was the most strongly related to mortality (χ² = 23.60, p = 0.0000).

QT interval and QT dispersion increase in the elderly during laparoscopic cholecystectomy: A preliminary study

“…It is exhibited in patients with myocardial infarction, subarachnoid hemorrhage and diabetes mellitus. 5,6,[17][18][19][20] In the present study, however, no arrhythmic events were observed during laparoscopic cholecystectomy in both elderly and younger patients. This may be due to the fact that patients with cardiac diseases were not included in this study.…”

“…[3][4][5][6] Dispersion of QT interval (QTD) defined as maximal QT interval minus minimal QT interval on 12 leads of the surface electrocardiogram (ECG) reflects regional heterogeneity of ventricular repolarization, 3 and has been reported to [4][5][6] The effect of intraperitoneal CO 2 insufflation on the QTD during laparoscopy is of considerable interest, and the effect of a longer duration of CO 2 insufflation on the QTD during laparoscopy remains unclear.…”

Dispersion of QT interval in premature ventricular beats is not an independent marker for inducible sustained ventricular tachycardia

“…Difference from the previous studies from Dabrowski (24)(25)(26) showing QT dispersion of ventricular premature beat is an independent risk for arryhthmic events, the present study demonstrates that QTd-V had a similiar accuracy compared with that of other noninvasive methods used in previous studies for discriminating between patients with different susceptibilities to ventricular tachyarrhythmias and does not provide additional independent diagnostic information. However, measurament of QT dispersion is easy, inexpensive and noninvasive but because measurement of QT interval and its dispersion are subject to introbserver and interobserver variability (28,29) and the problems with identification of the end of the T wave and as QTd-V is a dependent risk factor, the measurement of QTd-V should not be included in the noninvasive evaluation of arrhythmic risk.…”

“…These findings confirm the previous report of Dabrowski that demostrate a sigificant relationship between QTd-V and risk of arrhyhmic events (24)(25)(26). These observations are consistent with the hypothesis that QT dispersion on the standard ECG is a marker of underlying regional inhomogenity of ventricular repolarization that can be associated with reentrant VT.…”

“…There are only several reports studying the clinical significance of QT interval dispersion measured in spontaneous ventricular beats (QTd-V) (24)(25)(26) showing significant relationship between QTd-V and the risk of arrhytmic events.…”