T wave peak-to-end interval and QT dispersion in acquired long QT syndrome: a new index for arrhythmogenicity

Abstract

QT dispersion (QTD) on 12-lead ECGs has been proposed as a marker of malignant ventricular tachyarrhythmias, and increased QTD has been reported in long QT syndrome (LQTS). On the other hand, it has been demonstrated that transmural dispersion is associated with ventricular tachyarrhythmias in an experimental model. However, the precise type of QTD or transmural dispersion that contributes most to ventricular tachyarrhythmias in patients with LQTS remains unclear. We evaluated 27 patients with acquired LQTS. These patients were divided into two groups: group A (n =12), patients with polymorphic ventricular tachycardia [torsades de pointes (TdP)], and group B (n =15), patients without TdP. The QT intervals were corrected using Bazett's formula. QTD was measured as the difference between the maximum and the minimum QT intervals, and T wave peak-to-end interval divided by the QT interval (Tpe) in the V5 lead was measured as a new index. Both the corrected QTD (QTDc) and Tpe were significantly larger in group A than in group B. Logistic regression analysis revealed that a reliable predictor for TdP in the QT variables in these patients was not QTDc but Tpe. Cumulative frequency distributions revealed that a Tpe of 0.28 is a good cut-off point for TdP. Tpe did not correlate with the corrected maximum QT interval, whereas the QTDc did correlate with this parameter. In conclusion, Tpe may be the best predictor for TdP in patients with acquired LQTS.

Prolonged Tp-e interval and Tp-e/QT correlates well with modified Rodnan skin severity score in patients with systemic sclerosis

“…Previous studies have shown that prolongation of the Tp-e interval is associated with increased mortality in Brugada syndrome, hypertrophic cardiomyopathy, and in patients undergoing primary percutaneous coronary intervention for myocardial infarction [13,22,23]. Yamaguchi et al [24] found that the Tp-e/QT ratio is a superior predictor of torsades de pointes than either QTc interval or QTd in patients with long QT syndrome (LQTS). Likewise, QTc did not reach statistical significance between the two groups in our study.…”

Effects of obstructive sleep apnoea on heart rhythm

“…2) [78,81]. A prolonging of the TpTe interval to .100 ms is proposed to be associated with increased vulnerability for the occurrence of early after-depolarisations and, thus, ventricular tachycardia and SCD [82][83][84].…”

The Relationship between Tpeak-end Interval Duration and Tpeak-end/QT Ratio, and Arrhythmias in Patients with Coronary Slow Flow

“…QTc interval was the QT interval corrected with the Bazett's formula (QT/√RR) (16). Besides, Tp-e was defined as the interval from the peak of a positive T wave or the nadir of a negative T wave to the end of the T wave in the tail method (17). In the tangent method, Tp-e (Tp-e tangent) was defined as the time from the peak of the T wave to the intersection between the tangent line and the isoelectric line (9, 18) ( Figure 1).…”