Dynamics of cardiac autonomic regulation during isometric sustained weight test in hypertensive patients

Background: Fingolimod modulates sphingosine-1-phosphate receptors that are also found in cardiovascular tissue. Objective: To investigate the effects of fingolimod on cardiac autonomic regulation prospectively. Methods: Twenty-seven relapsing–remitting multiple sclerosis patients underwent 24-hour electrocardiogram recording before, at the first day of fingolimod treatment (1d) and after three months of continuous dosing (3mo). The time interval between two consecutive R-peaks (RR-interval) was measured. Cardiac autonomic regulation was assessed by the various parameters of heart rate variability. Parasympathetic stimulation prolongs the RR-interval and increases heart rate variability while the effects of sympathetic stimulation are mainly the opposite. The low frequency/high frequency ratio reflects sympathovagal balance. Results: From baseline to 1d, a prolongation of the RR-interval ( P<0.001), an increase in the values of various heart rate variability parameters ( P<0.05 to P<0.001) and a decrease in the low frequency/high frequency ratio ( P<0.05) were demonstrated. At 3mo, although the RR-interval remained longer ( P<0.01), the values of various heart rate variability parameters were lower ( P<0.01 to P<0.001) as compared to baseline. At 3mo, the low frequency/high frequency ratio ( P<0.05) was higher in men than in women although no such difference was found at baseline or at 1d. Conclusions: After an initial increase in parasympathetic regulation, continuous fingolimod dosing shifts cardiac autonomic regulation towards sympathetic predominance, especially in men. Careful follow-up of fingolimod-treated relapsing–remitting multiple sclerosis patients is warranted as sympathetic predominance associates generally with impaired outcome. ClinicalTrials.cov: NCT01704183

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Binary symbolic dynamics analysis to detect stress-associated changes of nonstationary heart rate variability

Scientific Reports ◽

10.1038/s41598-020-72034-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Conrad Spellenberg ◽

Peter Heusser ◽

Arndt Büssing ◽

Andreas Savelsbergh ◽

Dirk Cysarz

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Psychological Stress ◽

Symbolic Dynamics ◽

Acute Stress ◽

Stress Test ◽

Autonomic Regulation ◽

Rr Interval ◽

Cardiac Autonomic Regulation ◽

Acute Psychological Stress

Abstract Psychological stress may have harmful physiological effects and result in deteriorating health. Acute psychological stress acts also on cardiac autonomic regulation and may lead to nonstationarities in the interbeat interval series. We address the requirement of stationary RR interval series to calculate frequency domain parameters of heart rate variability (HRV) and use binary symbolic dynamics derived from RR interval differences to overcome this obstacle. 24 healthy subjects (12 female, 20–35 years) completed the following procedure: waiting period, Trier Social Stress Test to induce acute psychological stress, recovery period. An electrocardiogram was recorded throughout the procedure and HRV parameters were calculated for nine 5-min periods. Nonstationarities in RR interval series were present in all periods. During acute stress the average RR interval and SDNN decreased compared to rest before and after the stress test. Neither low frequency oscillations (LF), high frequency oscillations (HF) nor LF/HF could unambiguously reflect changes during acute stress in comparison to rest. Pattern categories derived from binary symbolic dynamics clearly identified acute stress and accompanying alterations of cardiac autonomic regulation. Methods based on RR interval differences like binary symbolic dynamics should be preferred to overcome issues related to nonstationarities.

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