Tpeak-Tend and Tpeak-Tend dispersion as risk factors for ventricular tachycardia/ventricular fibrillation in patients with the Brugada syndrome

Abstract

Objectives: Our objective in this study was to evaluate Tpeak-Tend interval (Tp-e) and other electrocardiographic parameters as risk factors for recurrence of life-threatening cardiac events in patients with the Brugada syndrome (BS).

Background: The Tp-e interval in the electrocardiogram (ECG) has been reported to predict life-threatening arrhythmias in the long QT syndrome.

Methods: Twenty-nine patients with the ECG pattern of BS and 29 healthy age- and gender-matched controls were studied. The follow-up period was 42.65 +/- 24.42 months (range 11 to 108 months).

Results: Upon presentation, five patients had suffered aborted sudden death, five syncope, and two presyncope. Eleven patients with the ECG pattern of BS had a prolonged (>460 ms) QTc in V2 but usually not in inferior or left leads. No patient had abnormally prolonged QT dispersion. Programmed electrical stimulation induced ventricular tachycardia/fibrillation in 5 out of 26 patients. Inducibility did not predict recurrence of events. Cardioverter-defibrillators were implanted in 14 patients (all symptomatic and two asymptomatic). During follow-up, nine symptomatic patients experienced recurrences. Previous cardiac events and a QTc >460 ms in V2 were significant risk factors (p = 0.00002 and p = 0.03, respectively). Tp-e and Tp-e dispersion were significantly prolonged in patients with recurrences versus patients without events (104.4 and 35.6 ms vs. 87.4 and 23.2 ms; p = 0.006 and p = 0.03, respectively) or controls (90.7 and 17.9 ms; p = 0.02 and p = 0.001, respectively).

Conclusions: Our study demonstrates significant correlation between previous events, QTc >460 ms in V2, Tp-e, and Tp-e dispersion and occurrence of life-threatening arrhythmic events, suggesting that these parameters may be useful in risk stratification of patients with the Brugada syndrome.

Figure 1

Precordial leads of the electrocardiogram (ECG) of a patient with the Brugada syndrome with recurrences (A), a Brugada-type ECG (B), and a control case (C). Numbers depict measured values for QT, QTpeak (QTp) and Tpeak-Tend interval (Tp-e). All values are in ms. T waves <1.5 mm were not measured.

Figure 2

Kaplan-Meier analysis of arrhythmic events during follow-up depending on Tpeak-Tend interval (Tp-e) ≥100 ms or Tp-e <100 ms.

Figure 3

Tpeak-Tend interval (Tp-e) receiver-operating characteristic (ROC) curve. The cut point that better optimizes the values of sensibility and specificity are for values ≥100 ms.

Figure 4

Kaplan-Meier analysis of arrhythmic events during follow-up depending on Tpeak-Tend interval (Tp-e) dispersion >20 ms or Tp-e dispersion ≤20 ms.

Figure 5

Tpeak-Tend interval (Tp-e) dispersion receiver-operating characteristic (ROC) curve. The cut point that better optimizes the values of sensibility and specificity are for values >20 ms.