Heart Rate Variability for Quantification of Autonomic Dysfunction in Fibromyalgia

Area of Science:

• Cardiology
• Neurology
• Autonomic Neuroscience

Background:

• Fibromyalgia is a complex chronic pain condition.
• Autonomic dysfunction is increasingly recognized in fibromyalgia patients.
• Heart rate variability (HRV) offers a non-invasive method to assess autonomic nervous system (ANS) function.

Purpose of the Study:

• To compare HRV parameters between fibromyalgia patients and healthy controls.
• To investigate the relationship between HRV metrics and the severity of autonomic symptoms in fibromyalgia.

Main Methods:

• A case-control study involving 16 fibromyalgia patients and 16 healthy controls.
• Time-domain HRV analysis including SDNN/RMSSD and R-R interval variations under different breathing conditions.
• Assessment of autonomic symptom severity using the Composite Autonomic Symptom Scale 31 (COMPASS 31).

Main Results:

• Fibromyalgia patients exhibited significantly higher SDNN/RMSSD ratios during quiet and controlled breathing compared to controls.
• Reduced differences between longest and shortest R-R intervals during the Valsalva maneuver were observed in fibromyalgia patients.
• A negative correlation was found between COMPASS 31 scores and SDNN/RMSSD values during controlled breathing.

Conclusions:

• The SDNN/RMSSD ratio is a sensitive indicator of autonomic nervous system dysfunction in fibromyalgia.
• This HRV parameter can effectively quantify subjective autonomic symptoms experienced by fibromyalgia patients.