Chronic high-intensity vagus nerve stimulation significantly improved intrinsic heart rate recovery by 16.3% and left ventricular ejection fraction by 34.4% over 36 months compared to screening.
Observational (n=75)
Yes
Does chronic vagus nerve stimulation improve intrinsic heart rate recovery and left ventricular ejection fraction in patients with HFrEF?
Chronic high-intensity vagus nerve stimulation is associated with sustained, multi-year improvements in autonomic tone (intrinsic heart rate recovery and turbulence) and left ventricular ejection fraction in patients with HFrEF.
Effect estimate: 16.3% improvement
Absolute Event Rate: 10.3% vs 12.3%
p-value: p=<0.0001
PURPOSE: Disturbed autonomic function is implicated in high mortality rates in heart failure patients. High-intensity vagus nerve stimulation therapy was shown to improve intrinsic heart rate recovery and left ventricular ejection fraction over a period of 1 year. Whether these beneficial effects are sustained across multiple years and are related to improved baroreceptor response was unknown. METHODS: All patients (n = 21) enrolled in the ANTHEM-HF clinical trial (NCT01823887, registered 4/3/2013) with 24 h ambulatory electrocardiograms at all time points and 54 normal subjects (PhysioNet database) were included. Intrinsic heart rate recovery, based on ~ 2000 spontaneous daily activity-induced heart rate acceleration/deceleration events per patient, was analyzed at screening and after 12, 24, and 36 months of chronic vagus nerve stimulation therapy (10 or 5 Hz, 250 μs pulse width, 18% duty cycle, maximum tolerable current amplitude). RESULTS: In response to chronic high-intensity vagus nerve stimulation (≥ 2.0 mA), intrinsic heart rate recovery (all time points, p < 0.0001), heart rate turbulence slope, an indicator of baroreceptor reflex gain (all, p ≤ 0.02), and left ventricular ejection fraction (all, p ≤ 0.04) were improved over screening at 12, 24, and 36 months. Intrinsic heart rate recovery and heart rate turbulence slope were inversely correlated at both screening (r = 0.67, p < 0.002) and 36 months (r = 0.78, p < 0.005). CONCLUSION: This non-randomized study provides evidence of an association between improvement in intrinsic heart rate recovery and left ventricular ejection fraction during high-intensity vagus nerve stimulation for a period of ≥ 3 years. Correlated favorable effects on heart rate turbulence slope implicate enhanced baroreceptor function in response to chronic, continuously cyclic vagus nerve stimulation as a physiologic mechanism.
Nearing et al. (Tue,) conducted a observational in Heart failure with reduced ejection fraction (n=75). Chronic vagus nerve stimulation vs. Screening (baseline) was evaluated on Intrinsic heart rate recovery (IHRR) at 36 months in high-intensity stimulation group (16.3% improvement, p=<0.0001). Chronic high-intensity vagus nerve stimulation significantly improved intrinsic heart rate recovery by 16.3% and left ventricular ejection fraction by 34.4% over 36 months compared to screening.