Central Pressure Variability After Low-Level Tragus Stimulation in Acute Decompensated Heart Failure

Increased variability in central aortic systolic pressure (CASP) and pulse pressure (PP) are predictors of poor cardiovascular disease outcomes. Low-level tragus stimulation (LLTS) is a noninvasive method to reduce sympathetic tone via vagal afferent fibers. It is unknown if LLTS has a favorable effect on elevated variability in CASP and PP in patients with acute decompensated heart failure (HF) (ADHF).

Patients hospitalized for ADHF after initial stabilization (median 80 years, males 60%) were randomly assigned to active or sham group, and LLTS (20 Hz, 1 mA) was delivered using an ear clip attached to the tragus (active group) or the earlobe (sham group) for 1 hour daily over 5 days. The variability of PP and CASP was measured before and after each stimulation.

Each of SD, CV, and δ in PP, CASP, radial augmentation index (rAI), %PP variation (PPV), and PP × heart rate (HR) was significantly decreased after stimulation in the active group (n = 8) (all P < 0.05), while δ in CASP was significantly increased after stimulation in the sham group (n = 8) (P < 0.05). All the changes in SD, CV, and δ in PP, CASP, rAI, %PPV, and PP × HR before and after stimulation were also significantly different between active and sham groups (all P < 0.05).

In this proof-of-concept study, LLTS led to a better hemodynamic profile, as evident in variability reduction in PP, CASP, and rAI. Further studies are warranted to study the long-term hemodynamic effects of LLTS on HF.Clinical trial registration: UMIN000044121.