An Integrative Literature Review of Heart Rate Variability Measures to Determine Autonomic Nervous System Responsiveness Using Pharmacological Manipulation.

The included studies used different drugs, doses, routes, recording lengths, sampling rates, and HRV metrics, so results are hard to compare. Human studies often had small, mostly male samples, and females were underrepresented, so sex differences were mostly not tested. The review included studies regardless of quality score because the appraisal tool has no cut point for acceptable quality. Short-term HRV measures have not yet been shown to be consistently predictive of cardiovascular outcomes compared with long-term measures. Only English-language articles were searched, which may limit generalizability. The review did not pool patient outcomes, so it cannot show that HRV changes or autonomic drugs improve patient care.

The article is tagged as NIH intramural research support, and the authors declared no potential conflicts of interest.

Do not read these HRV changes as proof that any treatment improves cardiovascular outcomes. The review synthesized pharmacologic manipulation studies, not patient outcomes, and it says short-term HRV measures have not yet been shown to be consistently predictive of cardiovascular outcomes.