Disturbances of autonomic nervous system and gastric activity in response to visceral stimulation in functional dyspepsia patients

Introduction
Functional dyspepsia (FD) is mainly caused by gastric hypersensitivity and impaired gastric motility.

Aim
The aim of the study was to evaluate the effect of a meal on autonomic nervous system (ANS) activity and gastric function in patients with dyspepsia.

Material and methods
The study included 38 patients with functional dyspepsia (age: 37.8 ±11.2 years) and 38 healthy volunteers (age: 39.8 ±11.1 years). Simultaneous recordings of electrogastrography (EGG) and electrocardiography (ECG) with heart rate variability (HRV) analysis were performed in the fasting state and after administration of a standard meal.

Results
EGG. In fasting dyspepsia group, lower normogastria (51.62 ±19.62 vs. 79.13 ±14.12%; p = 0.004) and average percentage of slow wave coupling (APSWC) (51.11 ±13.25 vs. 69.22 ±14.18%; p = 0.001) were observed compared to the control group. After a meal, in FD patients bradygastria increased from 5.6 ±3.1% to 12.2 ±6.3% (p = 0.01); APSWC increased but did not reach the value of the control group (77.3 ±14.1%); and the increase in the amplitude of slow waves after a meal was smaller (by 49%) than that in the control group (by 215%; p = 0.0001). ANS. Preprandially, the parameters of HRV spectral analysis were significantly lower in FD patients than in the control group (LF; p = 0.03; HF; p = 0.01). Postprandially, FD patients showed an increase in LF (p = 0.001) and HF (p = 0.02) indices, similar to the control group, but the parameters values were lower.

Conclusions
The postprandial parasympathetic response was reduced in patients with dyspepsia. The decreased reactivity of the ANS in functional disorders contributes to gastric myoelectric dysfunction as manifested by clinical signs of dyspepsia.