# Effects of sugammadex on heart rate variability in anesthetized male rats

## TL;DR

This study investigates how sugammadex affects heart rate variability in anesthetized rats, suggesting it influences heart rate through vagal activation.

## Contribution

The study reveals that sugammadex increases heart rate variability via vagal activation in anesthetized rats.

## Key findings

- Sugammadex prolonged the mean R-R interval and increased HRV indices.
- Vagotomy abolished sugammadex's effects on HRV, indicating vagal involvement.
- Rocuronium prior to sugammadex did not alter sugammadex's HRV effects.

## Abstract

The administration of sugammadex has been associated with bradycardia and rarely asystole; however, the underlying mechanisms remain unclear. We examined heart rate variability (HRV) as an index of autonomic nervous system activity and investigated the effects of sugammadex on HRV in α‐chloralose and urethane anesthetized male rats. In protocol 1, we examined the effect of intravenous administration of sugammadex (10 mg/kg) alone. In protocol 2, sugammadex was administered 3 min after the administration of rocuronium bromide. In protocol 3, the effect of sugammadex was assessed after vagotomy. Sugammadex significantly prolonged the mean R‐R interval and increased time domain HRV indices, total power, high‐frequency power, and low‐frequency power. Rocuronium prior to sugammadex did not affect sugammadex‐induced percent changes in HRV indices. Prior vagotomy abolished the effects of sugammadex on HRV. These results suggest that sugammadex prolonged the mean R‐R interval and augmented HRV indices via vagal activation.