Heart rate variability as an assessment of cardiovascular status

In summary, HRV is a useful tool for cardiovascular risk stratification and assessment of sympathovagal balance. It has been shown to be a useful investigative tool in anesthesia to study autonomic balance and dysfunction but has limitations with regard to a depth-of-anesthesia monitor because of the confounding effects of multiple drugs and surgical stimuli. When assessing HRV, it is important to understand the limitations of the methodology. In particular, absolute power is not a surrogate of autonomic tone, but the relationship between the power in the different frequency bands may better reflect autonomic balance.