Objectives: The hypothesis of autonomic nervous system involvement in pathophysiology in the patients with fibromyalgia has been addressed and tested time and again but the existing reports are both contradictory and inconclusive. A complete knowledge of the degree of autonomic dysfunction in fibromyalgia patients would be more substantial. We conducted a comprehensive non-invasive study to investigate the complete autonomic profile of female patients with fibromyalgia.
Method: An autonomic function test using a standard battery and heart rate variability analysis in the 42 fibromyalgia patients as well as 42 age matched healthy controls was performed. Both autonomic activity (tone) and reactivity were measured. Autonomic tone (both time and frequency domain parameters) was measured using heart rate variability (HRV) analysis. Autonomic reactivity was measured using a standard battery of autonomic function tests.
Results: Resting blood pressure (both systolic and diastolic) was significantly higher in the fibromyalgia patients than controls. The time domain variables and HF% as recorded by HRV were significantly lower in the patients than the controls. The autonomic reactivity for sympathetic and parasympathetic nervous system was found to be within normal limits.
Interpretation: The cardiac autonomic function is normal and the autonomic reflex arc seems to be intact in the patients with fibromyalgia.