Fibromyalgia unplugged: Heart rate variability as a window to autonomic regulation
Background: The hallmarks of fibromyalgia (FM), a chronic pain syndrome, include tiredness, cognitive impairment, and extensive musculoskeletal discomfort. An imbalance in the autonomic nerve system may play a major role in its pathogenesis, leading to changes in visceral and cardiovascular control, according to mounting evidence. Heart rate variability (HRV) is a sensitive, non-invasive measure of sympathovagal balance and autonomic regulation. Aims and Objectives: The purpose of this study was to compare HRV indices between FM patients and age- and sex-matched healthy controls in order to evaluate autonomic dysfunction in FM utilizing short-term HRV analysis. Materials and Methods: Thirty patients with FM diagnosed using the 2016 updated American College of Rheumatology’s criteria, and 30 healthy volunteers were included in this cross-sectional research. In accordance with Task Force standards, standardized 5-min rested electrocardiograms were obtained, and HRV characteristics were examined in the time domains and frequency domains. The data were analyzed using Statistical Package for the Social Sciences 26.0, with t-tests for between-group comparisons. P<0.05 was considered statistically significant. Results: When compared to healthy controls, FM patients showed a significant decrease in HRV indicators. The RMSSD was 19.3±7.2 ms compared to 38.7 ± 10.1 ms (P<0.001*), and the mean standard deviation of NN intervals (SDNN) was 22.6±8.1 ms rather than 41.2±9.4 ms (P<0.001*). Frequency-domain measurements revealed a higher low-frequency/high-frequency (LF/HF) ratio (1.72±0.65 vs. 1.15±0.48, P=0.003*), indicating greater sympathetic dominance and decreased parasympathetic modulation, along with significantly lower LF power (315±120 ms2 vs. 520±160 ms2, P<0.001*) and HF power (210±98 ms2 vs. 450±142 ms2, P<0.001*). Conclusion: Significantly decreased HRV in both the temporal and frequency domains is a symptom of substantial autonomic dysfunction linked to FM. The concept of impaired central autonomic control in FM is supported by these data, which highlight a condition of sympathovagal imbalance. For determining the severity of an illness and tracking treatment plans meant to restore autonomic balance, HRV may be a helpful biomarker.
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