Noninvasive vagus nerve stimulation: A novel promising modulator for cardiac autonomic nerve system dysfunction

Abstract

Despite modern strategies, patients with cardiac diseases are still at high mortality rate due to neurohormonal activation and autonomic imbalance with increase in sympathetic activity and withdrawal of vagal activity. It is well known that conventional vagus nerve stimulation (VNS) could suppress the sympathetic tone and enhance the vagal tone, and prevent and reverse cardiac remodeling to break the vicious cycle between autonomic imbalance and cardiac remodeling [ [1] Hamann J.J. Ruble S.B. Stolen C. Wang M. Gupta R.C. Rastogi S. et al. Vagus nerve stimulation improves left ventricular function in a canine model of chronic heart failure. Eur. J. Heart Fail. 2013; 15: 1319-1326 Crossref PubMed Scopus (80) Google Scholar ]. However, traditional VNS has to implant a bipolar electrode around the cervical vagus nerve and a generator subcutaneously in the chest wall. This may cause complication or side effects including wound infection, electrode malfunction, coughing, swallowing difficulty and dysphagia [ 2 Spuck S. Tronnier V. Orosz I. Schönweiler R. Sepehrnia A. Nowak G. Sperner J. Operative and technical complications of vagus nerve stimulator implantation. Neurosurgery. 2010; 67: 489-494 PubMed Google Scholar , 3 Elliott R.E. Morsi A. Kalhorn S.P. Marcus J. Sellin J. Kang M. et al. Vagus nerve stimulation in 436 consecutive patients with treatment-resistant epilepsy: long-term outcomes and predictors of response. Epilepsy Behav. 2011; 20: 57-63 Abstract Full Text Full Text PDF PubMed Scopus (225) Google Scholar ]. The potential noninvasive approach for VNS, a transcutaneous electrical stimulation of the auricular branch of the vagus nerve (ABVN), has been proven to be effective on cardiac protection against cardiac diseases induced by disordered autonomic tone [ [4] Yu L. Scherlag B.J. Li S. Fan Y. Dyer J. Male S. et al. Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve: a noninvasive approach to treat the initial phase of atrial fibrillation. Heart Rhythm. 2013; 10: 428-435 Abstract Full Text Full Text PDF PubMed Scopus (114) Google Scholar ].