Effects of electrostimulation of the vagus afferent endings in patients with coronary artery disease

Abstract

Background: In rats, low-frequency electroneurostimulation (ENS) of the ear afferent vagus endings and brainstem structures via transauricular electroacupuncture increases the parasympathetic tone of the autonomic nervous system. We examined the effects of ENS applied in the preoperative period in patients with coronary artery disease (CAD) who underwent coronary artery bypass grafting operations.

Methods: ENS was performed in a group of 10 patients with CAD who were classified as Canadian Cardiovascular Society class IV before operation. A second group of 10 patients with a similar degree of CAD comprised a control group. The efficacy of the procedure was evaluated on the basis of improvement in the patient's clinical course before and after operation. The presence of major inducible stress protein (HSP 70i) and the ATP content of the myocardium was determined in atrial tissue (part of the right heart auricle) from both groups of patients. Tissue from patients with Wolff-Parkinson-White (WPW) syndrome served as a control, non-ischemic, cardiac tissue.

Results: A course of 10 ENS procedures improved the patients' preoperative clinical course, producing a rapid reduction in their angina. By the end of the course, the patients no longer developed angina either at rest or after a moderate physical load, and their dependence on treatment with vasodilators had decreased considerably. Atrial tissue from patients with CAD who were treated with ENS was similar to that from patients with WPW in lcaking HSP 70i and in ATP content. In contrast, tissue from the control group of patients with CAD contained HSP 70i and had an increased content of ATP. The antianginal effect of neurostimulation lasted for at least 2-3 weeks after completion of the procedures. The postoperative recovery of patients treated with ENS was characterized by stable hemodynamics and sinus rhythm.

Conclusion: We conclude that ENS had a central vagotonic/sympatholytic influence on the heart, leading to the development of three main effects in patients with CAD: relief of anginal symptoms, diminution of some biochemical myocardial signs of the disease, and an increase in the heart's tolerance of operative reperfusion damage.