Effects of remimazolam and propofol on parasympathetic activity during general anesthesia induction in patients with severe aortic stenosis: a randomized controlled trial utilizing high-frequency variability index

In this study, we aimed to compare the effects of remimazolam and propofol on parasympathetic activity during general anesthesia induction in patients with severe aortic stenosis using heart rate variability (HRV) analysis. In this single-center randomized controlled trial, 28 patients scheduled for elective transcatheter aortic valve replacement were assigned to receive either remimazolam or propofol for anesthesia induction at a tertiary emergency medical facility. Parasympathetic activity was assessed using the high-frequency variability index (HFVI), derived from spectral analysis of HRV based on electrocardiographic R–R intervals. HFVI was recorded for 3 min before and after induction. Remimazolam or propofol was administered at 6 mg/kg/h or 2.0 µg/ml via target-controlled infusion, respectively. The primary outcome was the difference in mean HFVI values recorded between the 3-min period before and after induction. Hemodynamic parameters, including mean blood pressure, heart rate, cardiac output, stroke volume variation, pulse pressure variation, and dynamic arterial elastance, were also measured. Baseline HFVI values did not differ significantly between groups. After induction, HFVI decreased significantly more in the remimazolam group than in the propofol group (ΔHFVI: 16 vs. 3, P = 0.010). Heart rate increased in the remimazolam group but decreased in the propofol group (P = 0.006). No significant intergroup differences were observed in other hemodynamic parameters. These findings suggest that remimazolam may be associated with distinct autonomic responses during anesthesia induction.