# Index of cardiac electrophysiological balance in patients with vasovagal syncope confirmed by head-up tilt test

## TL;DR

This study explores how a new index called ICEB helps understand heart function in patients with vasovagal syncope, a condition causing fainting.

## Contribution

The study introduces ICEB as a novel tool to assess cardiac electrophysiological balance in vasovagal syncope patients.

## Key findings

- Patients with vasovagal syncope had significantly lower ICEB and ICEBc compared to healthy controls.
- Type 2 vasovagal syncope showed the lowest ICEB and ICEBc levels.
- ICEB and ICEBc were not significantly correlated with asystole duration in Type 2 patients.

## Abstract

Vasovagal Syncope (VVS) is a transient loss of consciousness caused by reflex vasodilatation and/or bradycardia, typically triggered by orthostatic stress, emotion, or pain. It is the most common form of neurally mediated syncope, carries a benign prognosis, yet recurrent episodes impair quality of life and require risk stratification and tailored management. The Index of Cardiac Electrophysiological Balance (ICEB) is a novel index designed to quantify the ventricular depolarization—repolarization electrophysiological balance and exhibits a bidirectional relationship with autonomic nervous function. In this study, we investigated the changes in ICEB among patients with VVS.

The clinical data of 266 patients with VVS, confirmed by Head-up tilt test (HUTT) at Shaanxi Provincial People's Hospital from August 2021 to February 2025 were retrospectively collected as study group. A total of 201 healthy individuals who completed routine physical examinations during the same period were enrolled as the control group. Electrocardiogram (ECG) parameters (RR, P, QRS, QT) and ICEB were calculated and statistical analyzed during the HUTT in 5-minute supine phase or at rest.

The QT interval, corrected QT (QTc) interval, ICEB and corrected ICEB (ICEBc) were lower (P < 0.001, respectively) in VVS group than in control group, with Type 2 showing the lowest level, even lower than those in Type 1 and Type 3. Pearson's correlation coefficient indicated that there was no significant correlation between the shortened cardiac electrophysiological parameters and asystole duration in Type 2. After adjusting for age, sex, body mass index, systolic blood pressure and diastolic blood pressure, VVS patients still had significantly lower ICEB, ICEBc compared with the control group.

In our study, we tried to demonstrate the relationship between ICEB and VVS confirmed by HUTT. We indicate that ICEB and ICEBc were shortened in patients with VVS at baseline, which may be attributed to autonomic dysfunction.