Therapeutic responsiveness to vagus nerve stimulation in patients receiving beta-blockade for heart failure with reduced ejection fraction

BACKGROUND: The effect of beta-blockade (BB) on response to vagus nerve stimulation (VNS) has not been reported in patients with heart failure and reduced ejection fraction (HFrEF). In the ANTHEM-HF Study, 60 patients received chronic cervical VNS. Background pharmacological therapy remained unchanged during the study, and VNS intensity was stable once up-titrated. Significant improvement from baseline occurred in resting 24-hour heart rate (HR), 24-hour HR variability (SDNN), left ventricular EF (LVEF), 6-minute walk distance (6MWD), and quality of life (MLWHFS) at 6 months post-titration. We evaluated whether response to VNS was related to percentage of target BB dose (PTBBD) at baseline. METHODS: Patients were categorized by baseline PTBBD, then analyzed for changes from baseline in symptoms and function at 6 months after VNS titration. RESULTS: All patients received BB, either PTBBD ≥ 50 % (16 patients, 27 %; group 1) or PTBBD < 50 % (44 patients, 73 %; group 2). Heart rate, systolic blood pressure, LVEF, use of ACE/ARB, and use of MRA were similar between the two groups at baseline. Six months after up-titration, VNS reduced HR and significantly improved SDNN, LVEF, 6MWD, and MLWHFS equally in both groups. CONCLUSIONS: In the ANTHEM-HF study, VNS responsiveness appeared to be independent of the baseline BB dose administered.