Evaluation of autonomic disorders in miners with vibration disease

Abstract

Introduction. Autonomic disorders in the form of autonomic neuropathy develop in vibration disease already at the early stages. As the disease progresses, the compensatory mechanisms of autonomic regulation are depleted, which leads to a worse prognosis for life and an increased risk of sudden cardiac death in patients with a severe degree of autonomic neuropathy. 
 The aim of the study was to evaluate the severity of autonomic disorders and the preservation of compensatory reserves of autonomic regulation in patients with vibration disease. 
 Materials and methods. One hundred thirty six miners with a proven diagnosis of vibration disease and 60 apparently healthy men of similar age without complaints and who had never worked under the conditions of exposure to industrial vibration were examined. Heart rate variability was analyzed at rest and during an active orthostatic test.
 Results. A decrease in the spectral parameters of heart rate variability in the patients with vibration disease was revealed. In a subgroup of the patients with an initially low level of very low frequency oscillations (less than 30 ms2/Hz), a decrease in the non-linear entropy index (less than 180) was determined; when performing an active orthostatic test, the power of very low frequency spectrum oscillations in the patients of this subgroup decreased by more than 50% of the initial values. In all patients with vibration disease under orthostatic load, a decrease in the oscillations of high and low frequencies of the spectrum of heart rate variability was revealed, whereas in the control group, the low frequency oscillation power remained at the initial level.
 Limitations. The study was limited to the evaluation of spectral and non-linear indices of heart rate variability in 136 miners with vibration disease. 
 Conclusion. The criteria for a severe course of autonomic neuropathy in the patients with vibration disease were identified: an initial decrease in the power of very low frequency oscillations and a non-linear entropy index of heart rate variability, as well as a decrease in the power of very low frequency oscillations by more than 50% during an orthostatic test. According to these criteria, in 40.4% of the miners with vibration disease, pronounced violations of the autonomic support with a lack of compensatory mechanisms of autonomic regulation were found to be detected.