Safety and Efficacy of His Bundle Pacing Validated by Extracardiac Vagal Nerve Stimulation
Safety and Efficacy of His Bundle Pacing Validated by Extracardiac Vagal Nerve Stimulation
Different studies for extracardiac vagal nerve stimulation (ECANS) have been published and
 confirmed the influence of the vagus nerve on automaticity and conduction properties of the
 sinus node, atria, atrioventricular node, as well as the His-Purkinje system (HPS) and
 ventricles. However, there are limited data on the clinical value and impact of ECANS as well
 as vagus nerve activity on the parameters of permanent His-bundle (HB) or left bundle branch
 (LBB) pacing. Moreover, there have been no prospective studies evaluating the feasibility and
 efficacy of ECANS and the management of ECANS-induced scenarios, such as an exit block,
 increase in pacing threshold, as well as vagally mediated arrhythmias and conduction
 abnormalities in patients with physiological conduction system pacing (HB/LBB pacing).

 The objective of the HIS-STORY study in humans is to evaluate the clinical value of ECANS in
 patients with HB/LBB pacing for further development of patient-centered management strategy.
This is a multicenter, prospective, open-label, randomized, interventional study enrolling
 patients with indications for permanent cardiac pacing according to the current European
 Society of Cardiology Guidelines on Cardiac Pacing. All participants will undergo permanent
 pacemaker implantation for HB or LBB pacing. Subsequently, an invasive electrophysiological
 study (EPS) and ECANS will be performed. The 2 x 2 randomisation will be performed, i.e.
 right vs left side superior ECANS and blinded for operator ultrasonography guided effective
 vs ineffective inferior vagal nerve stimulation). The randomisation will prove the
 feasibility and efficacy of superior ECANS and feasibility, efficacy, and reproducibility of
 ultrasonography guided inferior ECANS. All the measured parameters as well as demographic and
 clinical data will be recorded in the study database. Patients with an exit block or an
 increase in a pacing threshold of an HB/LBB electrode will be further managed by
 electrophysiologists from the research group. The management will be based on clinical
 assessment and patient's decision and may involve pacemaker reprogramming, pacemaker upgrade
 with a back-up pacing electrode implantation, or cardio-neuro-ablation.
Inclusion Criteria:

 -  signed informed consent form

 -  effective and stable HB or LBB pacing

 -  sinus rhythm during the intervention procedure

 Exclusion Criteria:

 -  contraindications to invasive EPS

 -  contraindications to general anesthesia

 -  contraindications to atropine administration (e.g., glaucoma)

 -  persistent atrial fibrillation or atrial flutter

 -  pregnancy

 -  diseases that may cause autonomic system neuropathy

 -  use of medications that may affect the parasympathetic system

 -  a history of cardiac surgery

 -  a history of ablation due to arrhythmia