Safety and Efficacy of His Bundle Pacing Validated by Extracardiac Vagal Nerve Stimulation

Overview

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.