Reduction of parasympathetic influence in fibromyalgia and its relationship with psychiatry in a specialized center of national reference

Abstract

Background. Fibromyalgia (FM) is characterized by chronic widespread pain, fatigue, sleep disturbances, depression, anxiety and dysautonomia (sympathetic hyperactivity).

Objective. To compare the heart rate variability (HRV) in women: 20 patients with FM vs. 20 controls by Holter 24 hrs.

Method. The measurement consisted of segments of five minutes. The frequency domain is determined by the natural logarithm of the LF/HF (Low/High Frecuencies) reason. Simple ANOVA was used for two groups of dimensional variables.

Results. The age range was 30-60 years. Nine presented psychiatric comorbidity: depression (77.7%) and anxiety (22.3%). There were differences (F = 24.45, p <0.0001) in LF/HF between groups in the nocturnal phase of registration (22 pm to 2 am) showing increased sympathetic activation in patients. In the SDNN index (standard deviation of intervals between heartbeats) there were significant differences on December 9 periods of record. In pNN50 index (percentage of intervals which differ by more than 50 milliseconds), the control group showed higher values of 6 to 12 hrs. Nocturnal variation was observed in 22 hrs (F = 22.37, p = 0.0001) until 6am (F = 30.27, p = 0.0001). The rMSSD indicator (square root of the mean of the differences in heart rate) showed higher values for the control group from 22 hrs (F = 67.71, p = 0.0001) until 6am (F = 80.35, p = 0.0001).

Discussion and conclusion. The results reflect the decreased parasympathetic influence in patients with FM.

This confirms the participation of parasympathetic nervous system in the pathophysiology of FM.