Role of QT dispersion and Tp-e interval after biventricular pacing in the incidence of sustained ventricular arrhythmias in patients with implanted cardiac resynchronization therapy device

Introduction: QT dispersion (QTd) and Tp-e interval show controversial results in incidence of sustained ventricular arrhythmias (SVA) in patients with heart failure (HF). In patients with implanted cardiac resynchronization therapy (CRT) device, there is a unique opportunity to record SVAs. The aim of this study was to evaluate the effects of QTd and Tp-e interval on the incidence of SVAs after simultaneous biventricular (Biv) pacing. Methods: In the present study, 31 consecutive patients with advanced HF and implanted CRT device were evaluated one year for possible SVAs, corrected QT (QTc), QTd, and Tp-e interval. Patients were divided into two groups; with (group 1) and without (group 2) SVAs. Results: Among the studied patients, 5 (16%) experienced SVAs. The intrinsic and Biv pacing QTd were 70.74 ± 18.00 and 89.26 ± 28.00 msec, and 95.09 ± 44 and 88.09 ± 33 msec in group 1 and group 2, respectively (P = 0.18 and P = 0.16, respectively). Tp-e was not different between the two groups. In group 1, QTc increased from 438.83 ± 64 msec to 488.24 ± 48 msec (P = 0.13), and in group 2, it decreased from 499.70 ± 65.00 msec to 480.00 ± 31.00 msec after simultaneous Biv pacing (P = 0.13). Conclusion: QTd, Tp-e, and QTc did not differ significantly after Biv pacing to show any positive effect on the incidence of SVAs in part due to the severity of changes which already occur in patients with advanced HF. QTc, QTd, and Tp-e showed little changes after Biv pacing and probably do not have a significant role in the incidence of SVAs.