Vagus nerve stimulation reduces ventricular arrhythmias and increases ventricular electrical stability

Abstract

Background Transcutaneous stimulation of the auricular branch of the vagus nerve (AB‐VNS) is a potentially noninvasive, inexpensive, and safe approach for vagus nerve stimulation that suppresses the induction and duration of atrial fibrillation and reduces sympathetic nerve outflow in healthy humans. Researchers have not determined whether AB‐VNS affects ventricular arrhythmias. Objective To evaluate the antiarrhythmic effects of noninvasive AB‐VNS on ventricular arrhythmias induced by myocardial infarction (MI). Methods and Results Twelve beagle dogs were randomly divided into the following two groups: a AB‐VNS group (coronary artery occlusion and noninvasive AB‐VNS) and a control group (coronary artery occlusion but without AB‐VNS). We examined spontaneous ventricular arrhythmias, ventricular electrophysiological properties, and cardiac function in conscious dogs. Morphology, fibrosis, and http://ultrastructures were also assessed. AB‐VNS significantly reduced the occurrence of spontaneous ventricular arrhythmias, including isolated premature ventricular complexes, ventricular couplets, ventricular bigeminy, ventricular trigeminy, and ventricular tachycardia. AB‐VNS effectively increased ventricular electrical stability, including significantly prolonged ventricular effective refractory periods, decreased the dispersion of effective refractory period, enhanced the ventricular fibrillation threshold, and decreased the maximum slope of the monophasic action potential duration restitution curve. AB‐VNS treatments alleviate ventricular interstitial fibrosis after MI. However, cardiac function was not improved, and MI‐induced ultrastructural changes in the myocardium were not reversed by 4 weeks of AB‐VNS. In addition, AB‐VNS for 4 weeks resulted in mild mitochondrial swelling within the neuronal axons of the auricular vagus fiber. Conclusions Noninvasive AB‐VNS reduces the occurrence of spontaneous ventricular arrhythmias in conscious dogs with MI. AB‐VNS increases ventricular electrical stability and alleviates ventricular interstitial fibrosis induced by MI.

Intermittent KHz-frequency electrical stimulation selectively engages small unmyelinated vagal afferents

“…Those functional effects can be registered noninvasively in humans and, after additional validation in large animal studies, could be combined into practical bedside systems for calibration and optimization of VNS-based therapies targeting different fibers and organs. For example, the B-fiber PSI could facilitate the optimization of VNS parameters to treat heart failure 19 or cardiac arrhythmias 88 , whereas the C-fiber PSI could act as an index of therapeutic effect in anti-inflammatory application of VNS 18,89 .…”

“…Therefore, the presented PSIs for different fibers, based on non-invasive measured physiological markers, can serve as an indicator of cVNS effectiveness on disease basis, for both at the time of electrode implantation and during follow up visits with health care providers. For example, the B-fiber PSI could facilitate the optimization of stimulation paradigms to treat heart failure 18 or cardiac arrhythmia 73 , whereas the C-fiber PSI could act as an index of therapeutic effect in antiinflammatory application of VNS 17 .…”

Cholinergic Elicitation Prevents Ventricular Remodeling via Alleviations of Myocardial Mitochondrial Injury Linked to Inflammation in Ischemia-Induced Chronic Heart Failure Rats

“…Each specimen was trimmed to approximately 1 mm 3 size and directly immersed in precooled 2.5% glutaraldehyde at 4°C overnight (Sbjbio, China, SBJ-0639M). Then, the fixed specimens were subjected to gradient dehydration in an acetone solution, uranium acetate staining, and lead citrate staining as described in our previous study [ 22 ]. The ultrastructure of cardiomyocytes was observed by a JEM-100 CXII TEM (JEOL, Japan, 80 kV), and images were captured at 500x magnification.…”

Non-invasive Autonomic Neuromodulation Is Opening New Landscapes for Cardiovascular Diseases

“…Nasi-Er et al also demonstrated that TS reduced the occurrence of spontaneous ventricular arrhythmias in conscious dogs with MI. The potential mechanisms of anti-ventricular arrhythmias may increase ventricular electrical stability and alleviate ventricular interstitial fibrosis (Nasi-Er et al, 2019). In a recent patient study, Yu et al (2017c) found that LL-ta-VNS reduced the incidence of reperfusion-related ventricular arrhythmias during the first 24 h after acute myocardial infarction and improved left ventricular function 5-7 days after reperfusion along with reduced venous cytokine levels.…”