Determinants of Nocturnal Cardiovascular Variability and Heart Rate Arousal Response in Restless Legs Syndrome (RLS)/Periodic Limb Movements (PLMS).

Sforza Sforza,Roche Roche,Pichot Pichot

doi:10.3390/jcm8101619

Sforza Sforza, Roche Roche + Show 1 more

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https://doi.org/10.3390/jcm8101619

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Abstract

Recent studies have suggested that restless legs syndrome is associated with an increased prevalence of cardiovascular diseases mediated by sympathetic activation occurring during periodic limb movements. The aim of this study was to establish which factors affect the degree of sympathetic activation during the basal condition and during periodic limb movements that may contribute to increased vascular risk. Fifty untreated restless legs syndrome patients aged 62.6 ± 11.1 y, free of cardiovascular diseases, were examined. Heart rate variability was calculated during wakefulness and all sleep stages, during periods with and without periodic limb movements. Heart rate changes before and after periodic limb movement onset were analyzed to assess the arousal response to periodic limb movements. Both analyses took into account the effects of age, gender, periodic limb movement duration, periodic limb movement index, periodic limb movement interval and periodicity, and magnitude of muscular activity (electromyogram power). Compared to periods without periodic limb movements, a significant increase in sympathetic activity occurred in periods with periodic limb movements, independent of age, sex and periodic limb movement characteristics. Data obtained from the cardiac arousal response to periodic limb movements showed that electromyogram power is the factor affecting sympathetic tonus. These results suggest that other factors, such as electromyogram power and individual susceptibility, should be considered in the assessment of the vascular risk related to restless legs syndrome.

Highlights

Restless legs syndrome (RLS) is a common sensorimotor neurological disease with a prevalence of up to 11% in the general population [1,2,3]; it is more frequent in females [4] and increases in prevalence with age [3]
When we considered periods with periodic limb movements (PLMS) compared to periods without PLMS, except for the high frequency (HF) values, there was a strong significant increase in very low frequency (VLF), low frequency (LF), and the LF/HF ratio (p < 0.001) in all non-rapid eye movement (REM) sleep stages, without a sympathetic increase in REM sleep
To the best of our knowledge, the present study is the first to examine, in a relatively large group of untreated RLS patients free of vascular diseases, the factors affecting the cardiac autonomic system during sleep and the pattern of cardiac response to PLMS, both implicated in the possible association between RLS-PLMS and cardiovascular risk

Summary

Introduction

Restless legs syndrome (RLS) is a common sensorimotor neurological disease with a prevalence of up to 11% in the general population [1,2,3]; it is more frequent in females [4] and increases in prevalence with age [3]. Clinical [5,6,7,8] and epidemiological studies [9,10] have established an association between RLS-PLMS and increased incidences of hypertension, cardiovascular diseases, and mortality after adjustment for cardiovascular risk factors, with a greater risk among those who have more frequent symptoms [11] and a RLS diagnosis for more than 3 years [3,9]. We know that RLS/PLMS may induce a nocturnal increase in cardiac sympathetic activity [17] and blood pressure [18] as a consequence of two factors: sleep fragmentation and PLMS itself. Sleep fragmentation does not seem to play a key role in vascular risk, since not all PLMS are associated with cortical arousal [17]. It must be noted that these results were obtained in small samples without data on the presence of other health problems and on vascular medications that may have affected the validity of the results

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