Effect of stimulating the auricular branch of the vagus nerve on the heart rate in patients with severe chronic heart failure

Abstract

A study was made to evaluate the prospects of improving the cardiac function by electrical stimulation of the auricular branch of the vagus nerve in patients with severe chronic heart failure (CHF). Sympathetic hyperactivity and the cardiac function were evaluated by 24-hour ECG monitoring, echocardiography, and a 6-min walk test. At the time of enrollment into the study, patients had a heart rate (HR) of more than 60 bpm, a left ventricular (LV) ejection fraction (EF) of less than 40%, and CHF NYHA functional class (FC) III or IV even with well tolerated medications. Control-group patients (n = 7) did not show significant changes in the functional state of the heart after sham treatment. In the test group (n = 44), a significant increase in LV EF and a decrease in end-systolic volume were induced by electrical pulse stimulation of the auricular branch. A decrease in HR was documented in 34 patients; CHF FC decreased by one or two grades in 40 patients. The changes were assumed to reflect new balance achieved in the autonomic regulation of the heart to contribute to sustaining competence of the myocardium. Electrical pulse stimulation of the auricular branch of the vagus nerve was concluded to provide a safe and efficacious addition to drug therapy in patients with severe CHF.