Simulation of Hemodynamic Responses to the Valsalva Maneuver: An Integrative Computational Model of the Cardiovascular System and the Autonomic Nervous System

The control of cardiovascular system by autonomic nervous system using model-based analysis is very useful to predict blood flow and blood pressure at different locations of human body. The regulation of cardiovascular system by autonomic nervous system is a very complex mechanism, so, an experimental-based model analysis may prove very helpful in studying and analysing its working properly. In this article, a very basic model of cardiovascular system is presented with blood pressure dynamics studied throughout the body. A new bond graph model of the autonomic nervous system embedded with baroreflex system is also presented. Autonomic regulation of ventricular contractility is represented by means of transfer functions. The results in terms of maximum ventricular elastance ([Formula: see text]) and end systolic pressure are shown for two experiments. Another alternative modelling approach to represent the function of nervous system action in blood pressure regulation in terms of an overwhelming controller has been proposed. This controller overwhelms the system properties and therefore helps in managing the unmodelled parts or properties of a system and makes it impeccable for controlling complex systems. All the results and simulations are obtained using Symbols Shakti® software (Bond graph software).

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Dual effect of the Valsalva maneuver on autonomic nervous system activity, intraocular pressure, Schlemm’s canal, and iridocorneal angle morphology

10.21203/rs.2.11861/v3 ◽

2019 ◽

Author(s):

Li Sun ◽

Wei Chen ◽

Zhiqi Chen ◽

Yan Xiang ◽

Jingmin Guo ◽

...

Keyword(s):

Nervous System ◽

Autonomic Nervous System ◽

Valsalva Maneuver ◽

Phase 2 ◽

Healthy Individuals ◽

Autonomic Nervous System Activity ◽

System Activity ◽

Autonomic Nervous ◽

Iridocorneal Angle ◽

Nervous System Activity

Abstract Background: The Valsalva maneuver (VM) is widely used in daily life, and has been reported to cause high intraocular pressure (IOP). This study aimed to assess changes in IOP, the Schlemm’s canal (SC), autonomic nervous system activity, and iridocorneal angle morphology in healthy individuals during different phases of the VM. Methods: The high frequency (HF) of heart rate (HR) variability, the ratio of low frequency power (LF) and HF (LF/HF), heart rate (HR), IOP, systolic (SBP) and diastolic blood pressure (DBP), the area of SC (SCAR), pupil diameter (PD), and some iridocorneal angle parameters (AOD500, ARA750, TIA500 and TISA500) were measured in 29 young healthy individuals at baseline, phase 2, and phase 4 of the VM. SBP and DBP were measured to calculate mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP). HF and the LF/HF ratio were recorded using Kubios HR variability premium software to evaluate autonomic nervous system activity. The profiles of the anterior chamber were captured by a Spectralis optical coherence tomography device (anterior segment module). Results: Compared with baseline values, in phase 2 of the VM, HR, LF/HF, IOP (15.1±2.7 vs. 18.8±3.5 mmHg, P < 0.001), SCAR(mean) (7712.112±2992.14 vs. 8921.12±4482.79 μm2, P = 0.039), and PD increased significantly, whereas MOPP, AOD500, TIA500, and TISA500 decreased significantly. In phase 4, DBP, MAP, AOD500, ARA750, TIA500and TISA500 were significantly lower than baseline value, while PD and HF were remarkably larger than baseline. The comparison between phase 2 and phase 4 showed that HR, IOP (18.8±3.5 vs. 14.7±2.9 mmHg, P < 0.001) and PD decreased significantly from phase 2 to phase 4, but there were no significant differences in other parameters. Conclusions: The expansion and collapse of the SC in different phases of the VM may arise from changes in autonomic nervous system activity. Further, the effects of the VM on IOP may be attributed to changes in blood flow and ocular anatomy.

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Dual effect of the Valsalva maneuver on autonomic nervous system activity, intraocular pressure, Schlemm’s canal, and iridocorneal angle morphology

BMC Ophthalmology ◽

10.1186/s12886-019-1275-y ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Li Sun ◽

Wei Chen ◽

Zhiqi Chen ◽

Yan Xiang ◽

Jingmin Guo ◽

...

Keyword(s):

Nervous System ◽

Autonomic Nervous System ◽

Valsalva Maneuver ◽

Phase 2 ◽

Healthy Individuals ◽

Autonomic Nervous System Activity ◽

System Activity ◽

Autonomic Nervous ◽

Iridocorneal Angle ◽

Nervous System Activity

Abstract Background The Valsalva maneuver (VM) is widely used in daily life, and has been reported to cause high intraocular pressure (IOP). This study aimed to assess changes in IOP, the Schlemm’s canal (SC), autonomic nervous system activity, and iridocorneal angle morphology in healthy individuals during different phases of the VM. Methods The high frequency (HF) of heart rate (HR) variability, the ratio of low frequency power (LF) and HF (LF/HF), heart rate (HR), IOP, systolic (SBP) and diastolic blood pressure (DBP), the area of SC (SCAR), pupil diameter (PD), and some iridocorneal angle parameters (AOD500, ARA750, TIA500 and TISA500) were measured in 29 young healthy individuals at baseline, phase 2, and phase 4 of the VM. SBP and DBP were measured to calculate mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP). HF and the LF/HF ratio were recorded using Kubios HR variability premium software to evaluate autonomic nervous system activity. The profiles of the anterior chamber were captured by a Spectralis optical coherence tomography device (anterior segment module). Results Compared with baseline values, in phase 2 of the VM, HR, LF/HF, IOP (15.1 ± 2.7 vs. 18.8 ± 3.5 mmHg, P < 0.001), SCAR (mean) (7712.112 ± 2992.14 vs. 8921.12 ± 4482.79 μm2, P = 0.039), and PD increased significantly, whereas MOPP, AOD500, TIA500, and TISA500 decreased significantly. In phase 4, DBP, MAP, AOD500, ARA750, TIA500and TISA500 were significantly lower than baseline value, while PD and HF were remarkably larger than baseline. The comparison between phase 2 and phase 4 showed that HR, IOP (18.8 ± 3.5 vs. 14.7 ± 2.9 mmHg, P < 0.001) and PD decreased significantly from phase 2 to phase 4, but there were no significant differences in other parameters. Conclusions The expansion and collapse of the SC in different phases of the VM may arise from changes in autonomic nervous system activity. Further, the effects of the VM on IOP may be attributed to changes in blood flow and ocular anatomy. Trial registration This observational study was approved by the ethics committee of Tongji Hospital (Registration Number: ChiCTR-OON-16007850, Date: 01.28.2016).

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Cardiovascular System Aboriginal and Send the Female Cardiovascular System Aboriginal and Migrant Female Population of the North of Russia: Models and Age Dynamics

Journal of New Medical Technologies ◽

10.12737/11833 ◽

2015 ◽

Vol 22 (2) ◽

pp. 43-49

Author(s):

Соколова ◽

A. Sokolova ◽

Еськов ◽

Valeriy Eskov ◽

Филатова ◽

...

Keyword(s):

Nervous System ◽

Autonomic Nervous System ◽

Cardiovascular System ◽

Age Groups ◽

Migrant Population ◽

Female Population ◽

Autonomic Nervous ◽

The North ◽

Prolongation Of Life ◽

The Russian Federation

Pathology of the cardiovascular system significantly affects the operational period, and improvement in cardiovascular system always and definitely can provide the prolongation of life. So the study of differences in life expectancy between aboriginal and migrant female population living in the North of the Russian Federation is based on the state of the cardiovascular system. To study the dynamics of the parameters of the autonomic nervous system in female population of Ugra - Ob of the North of Russia, the authors used the method of cardiorythm registration. It is defined that parasympathetic division (parameter SIM) dominates over the sympathetic division (parameter PAR) of the autonomic nervous system in the youngest age group of women. The authors found diametrically opposite dynamics of PAR in two age groups: migrant population has a high initial value at a young age (12.5.a.u.) in comparison with the natives (10,6 a.u. source). However, in older age, these differences remain (7,84 a.u. and 6,87 a.u. respectively). Description of the dynamics of increase of the sympathetic and downs parasympathetic effect was produced in the framework of the model of Verhulst-Pearl, i.e., systems with saturation. However, the parameters of RR-intervals in the migrant population have a parabolic dependence.

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