Sleep and circadian influences on cardiac  autonomic nervous system activity

To assess the separate contributions of the sleep and circadian systems to changes in cardiac autonomic nervous system (ANS) activity, 12 supine subjects participated in two 26-h constant routines, which were counterbalanced and separated by 1 wk. One routine did not permit sleep, whereas the second allowed the subjects to sleep during their normal sleep phase. Parasympathetic nervous system activity was assessed with respiratory sinus arrhythmia as measured from the spectral analysis of cardiac beat-to-beat intervals. Sympathetic nervous system activity was primarily assessed with the preejection period as estimated from impedance cardiography, although the 0.1-Hz peak from the spectral analysis of cardiac beat-to-beat intervals, the amplitude of the T wave in the electrocardiogram, and heart rate were also measured. Respiratory sinus arrhythymia showed a 24-h rhythm independent of sleep, whereas preejection period only showed a 24-h rhythm if sleep occurred. Thus the findings indicate that parasympathetic nervous system activity is mostly influenced by the circadian system, whereas sympathetic nervous system activity is mostly influenced by the sleep system.

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Hemodynamic Patterns and Spectral Analysis of Heart Rate Variability during Dialysis Hypotension

Journal of the American Society of Nephrology ◽

10.1681/asn.v10122577 ◽

1999 ◽

Vol 10 (12) ◽

pp. 2577-2584

Author(s):

MICHEL G. W. BARNAS ◽

WALTHER H. BOER ◽

HEIN A. KOOMANS

Keyword(s):

Heart Rate ◽

Nervous System ◽

Spectral Analysis ◽

Parasympathetic Nervous System ◽

Intradialytic Hypotension ◽

Intravascular Volume ◽

Autonomic Nervous System Activity ◽

System Activity ◽

Nervous System Activity ◽

Sympathetic Nervous

Abstract. Intradialytic hypotension, a major source of morbidity during hemodialysis and ultrafiltration, is often accompanied by paradoxical bradycardia. Relatively little is known about the sequential changes in autonomic nervous system activity up to and during the hypotensive episode. Continuous, beat-to-beat measurements of BP and heart rate were made during hemodialysis in patients prone (n = 8) and not prone (n = 11) to develop intradialytic hypotension. Off-line spectral analysis of heart rate variability (HRV) was performed to assess changes in autonomic nervous system activity during dialysis sessions both with and without hypotension. The low frequency (LF) component of HRV is thought to correlate with sympathetic nervous system activity, the high frequency (HF) component with that of the parasympathetic nervous system. In the sessions not complicated by symptomatic hypotension (n = 26), mean arterial BP (MAP) hardly fell, whereas heart rate increased from 77 ± 2 to 89 ± 5 bpm (P < 0.05). The LF component of HRV increased from 45.2 ± 5.0 normalized units (nu) to 59.9 ± 4.9 nu (P < 0.05), whereas the HF component fell from 54.8 ± 5.0 to 40.2 ± 4.4 nu (P < 0.05). These changes agree with compensatory baroreflex-mediated activation of the sympathetic nervous system (and suppressed parasympathetic activity) during ultrafiltration-induced intravascular volume depletion. In the sessions complicated by severe symptomatic hypotension (n = 22), the changes in heart rate and the results of spectral analysis of HRV were similar to those reported above up to the moment of sudden symptomatic (nausea, vomiting, dizziness, cramps) hypotension, whereas MAP had already fallen gradually from 94 ± 3 to 85 ± 3 mmHg (P < 0.05). The sudden further reduction in MAP (to 55 ± 2 mmHg, P < 0.02) was invariably accompanied by bradycardia (heart rate directly before hypotension 90 ± 2 bpm, during hypotension 69 ± 3 bpm, P < 0.002). The LF component of HRV fell from 62.8 ± 4.6 nu directly before to 40.0 ± 3.7 nu (P < 0.05) during hypotension, whereas the HF component increased from 37.9 ± 4.7 to 60.3 ± 3.7 nu (P < 0.05). These findings agree with activation of the cardiodepressor reflex, involving decreased sympathetic and increased parasympathetic nervous system activity, respectively. These findings indicate that activation of the sympatho-inhibitory cardiodepressor reflex (Bezold-Jarisch reflex), which is a physiologic response to a critical reduction in intravascular volume and cardiac filling, is the cause of sudden intradialytic hypotension.

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Vegetative disfunction and adaptive reserve potential in children born with fetus growth delay in the first 6 months of life

Pediatrician (St Petersburg) ◽

10.17816/ped7477-89 ◽

2016 ◽

Vol 7 (4) ◽

pp. 77-89 ◽

Cited By ~ 1

Author(s):

Dmitry O Ivanov ◽

Lyudmila V Kozlova ◽

Vitaly V Derevtsov

Keyword(s):

Nervous System ◽

Autonomic Nervous System ◽

Sympathetic Nervous System ◽

Sympathetic Nervous System Activity ◽

System Activity ◽

Autonomic Nervous ◽

Nervous System Activity ◽

Group I ◽

Sympathetic Nervous ◽

Group Ii

In the course of the research we assessed the status of the autonomic nervous system and adaptation in infants with intrauterine growth restriction (IUGR) during the first six months of life. We observed infants born after abnormal pregnancies with IUGR (Group I), infants born after abnormal pregnancies without IUGR (Group II) and virtually healthy infants (without pregnancy and labour complications) in Group III. Despite the complicated medical history, at birth Group I infants displayed the level of sympathetic nervous system activity comparable to the one in Group III infants and lower than the level in Group II infants. However, in Group I infants sympathetic nervous system activity was restricted and compensatory reserves were depleted, sympathicotonia was prevalent. Decrease in frequency of asympathicotonic responsiveness of the autonomic nervous system (from 36.11% to 16.67%) and increase in sufficient adaptation (from 27.78% to 33.33%) in Group I infants by the end of neonatal period of life are related to the treatment of the pregnant women, as we suppose. Despite the fact that by the age of three months the level of sympathetic nervous system activity in Group I infants was lower than that in Group II infants, Group I infants showed less intensive decrease in sympathetic activity level followed by more strain on compensatory reserves. By the age of six months the sympathetic nervous system activity had continued decreasing and was no longer significantly different in Group I and Group II infants. At the same time, Group I infants displayed more frequent hypersympathicotonias combined with asympathicotonic responsiveness of the autonomic nervous system (in 16.36%). The results of the research show that IUGR in infants is connected to high rate of hypersympathicotonia with asympathicotonic responsiveness of the autonomic nervous system, which results in higher frequency and intensity of clinical implications of autonomic nervous system dysfunction.

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