Effects of permanent cardiac pacing on ventricular repolarization when compared to cardioneuroablation

Introduction: The impact of cardioneuroablation (CNA) on ventricular repolarization by using corrected QT interval (QTc) measurements has been recently demonstrated. The effects of cardiac pacing (CP) on ventricular repolarization have not been studied in patients with vasovagal syncope (VVS). We sought to compare ventricular repolarization effects of CNA (group 1) with CP (group 2) in patients with VVS. Methods: We enrolled 69 patients with age 38 +/- 13 years (53.6% male), n = 47 in group 1 and n = 22 in group 2. Clinical diagnosis of cardioinhibitory type was supported by cardiac monitoring or tilt testing. QTc was calculated at baseline (time-1), at 24 h after ablation (time-2), and at 9-12 months (time-3) in the follow-up. Results: In the group 1, from time-1 to time-2, a significant shortening in QTcFredericia (from 403 +/- 27 to 382 +/- 27 ms, p < 0.0001), QTcFramingham (from 402 +/- 27 to 384 +/- 27 ms, p < 0.0001), and QTcHodges (from 405 +/- 26 to 388 +/- 24 ms, p < 0.0001) was observed which remained lower than baseline in time-3 (373 +/- 29, 376 +/- 27, and 378 +/- 27 ms, respectively). Although the difference between measurements in time-1 and time-2 was not statistically significant for QTcBazett, a significant shortening was detected between time-1 and time-3 (from 408 +/- 30 to 394 +/- 33, p = 0.005). In the group 2, there was no time-based changes on QTc measurements. In the linear mixed model analysis, the longitudinal reduction tendency in the QTcFredericia and QTcFramingham was more pronounced in group 1. Conclusions: Our results demonstrate that CNA reduces QTc levels through neuromodulation effect whereas CP has no effect on ventricular repolarization in patients with VVS. (c) 2021 Elsevier Inc. All rights reserved.