Electrical Stimulation of the Greater Auricular Nerve to Reduce Postoperative Atrial Fibrillation

Abstract

Background: Postoperative atrial fibrillation (POAF) occurs in up to 40% of patients undergoing cardiac surgery. Invasive stimulation of the vagal nerve previously demonstrated a reduced risk of POAF. Therefore, we examined the antiarrhythmic and anti-inflammatory effects of noninvasive low-level transcutaneous electrical stimulation (LLTS) of the greater auricular nerve in a pilot trial including patients undergoing cardiac surgery.

Methods: Patients were randomized into a sham (n=20) or a treatment group (n=20) for LLTS. After cardiac surgery, electrodes were applied in the triangular fossa of the ear. Stimulation (amplitude 1 mA, frequency 1 Hz for 40 minutes, followed by a 20 minutes break) was performed for up to 2 weeks after cardiac surgery. Heart rhythm was recorded continuously using an ECG during the observation period. CRP (C-reactive protein) and IL (interleukin)-6 plasma concentrations were measured immediately after surgery as well as on day 2 and 7 postsurgery.

Results: Patients receiving LLTS had a significantly reduced occurrence of POAF (4 of 20) when compared with controls (11 of 20, P=0.022) during a similar mean Holter recording period. The median duration of POAF was comparable between the treatment and the control group (878 [249; 1660] minutes versus 489 [148; 1775] minutes; P=0.661). No effect of LLTS on CRP or IL-6 levels was detectable.

Conclusions: LLTS of the greater auricular nerve may be a potential therapy for POAF. We demonstrated the feasibility to conduct a randomized trial of neurostimulation as an outlay for a multisite clinical trial.

Keywords: C-reactive protein; atrial fibrillation; electrode; heart; interleukin.