Low-frequency oscillations in arterial pressure and heart rate: a simple computer model

1989 ◽  
Vol 256 (6) ◽  
pp. H1573-H1579 ◽  
Author(s):  
J. B. Madwed ◽  
P. Albrecht ◽  
R. G. Mark ◽  
R. J. Cohen
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Computer Model ◽  
Low Frequency ◽  
Beta Adrenergic ◽  
Simple Computer ◽  
Effector Mechanism ◽  
Arterial Blood ◽  
Low Frequency Oscillations ◽  
Effector Mechanisms

We have previously reported that low-frequency oscillations in arterial blood pressure (ABP) and heart rate (HR) occur when conscious dogs experience severe blood loss. These low-frequency oscillations are generated by enhancement of the sympathetic nervous system and inhibition of the parasympathetic nervous system. We have developed a simple computer model to elucidate those properties critical to the generation of these oscillations. Our model incorporates several important features: 1) arterial baroreceptor feedback loops, which relate ABP to targeted HR and total peripheral resistance (TPR) values; 2) two effector outputs, HR and TPR, which are controlled by the outputs of vagal, beta-adrenergic, and alpha-adrenergic effector mechanisms; 3) a fixed beat-to-beat stroke volume; and 4) a wind-kessel model, which represents the peripheral circulation. Each effector mechanism is modeled as a low-pass filter in series with a delay. The vagal effector mechanism slows the HR after a 100-ms delay and reaches maximal HR at that time. The beta-adrenergic effector mechanism speeds HR after a 2.5-s delay and then increases to maximal HR 7.5 s later. The alpha-adrenergic effector mechanism begins vasoconstriction after a 5-s delay and then reaches maximal contraction 15 s later. Computer simulations of inhibition of the vagal effector mechanism and activation of the adrenergic effector mechanisms elicit low-frequency oscillations in ABP and HR. These oscillations are similar to those observed experimentally in the dog during hemorrhage. We conclude that the slow temporal response of the alpha-adrenergic effector mechanism controlling TPR is the critical element in predicting the observed low-frequency oscillations in ABP and HR.

Role of cardiac output in mediating arterial blood pressure oscillations

1996 ◽  
Vol 271 (3) ◽  
pp. R641-R646 ◽  
Author(s):  
D. S. O'Leary ◽  
D. J. Woodbury
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Low Frequency ◽  
Left Ventricular ◽  
Right Atrial ◽  
Total Power ◽  
Av Block ◽  
Arterial Blood ◽  
Low Frequency Oscillations

The objective of this study was to determine the role of cardiac output in mediating spontaneous fluctuations in mean arterial pressure (MAP) conscious dogs. Dogs were chronically instrumented to monitor MAP and cardiac output. Atrioventricular (AV) block was induced, and left ventricular and right atrial electrodes were implanted. After recovery, MAP was observed for 5 min under two conditions: 1) normal variation in heart rate and cardiac output via triggering the ventricular stimulator with each atrial depolarization (effectively reversing the AV block, AV-linked stimulation) and 2) computer control of ventricular rate to maintain cardiac output constant on a by-beat basis at the same level as observed during normal variations in heart rate and cardiac output. When cardiac output was held constant, large-amplitude, low-frequency oscillations in MAP were readily apparent. Spectral analysis by fast Fourier transform revealed that during constant cardiac output the power observed at low frequencies in the MAP spectrum represented 95.0 +/- 2.7% of the total power compared with 75.5 +/- 4.6% during normal variations in heart rate and cardiac output (P < 0.05). In addition, when cardiac output was held constant, the power observed at higher frequencies markedly decreased from 24.5 +/- 4.6% of total power during AV-linked stimulation to only 5.0 +/- 2.7% of total power during constant cardiac output (P < 0.05). We conclude that low-frequency oscillations in MAP are due to changes in peripheral resistance, whereas a significant amount of high-frequency changes in MAP stems from spontaneous changes in cardiac output.

Heart rate response to hemorrhage-induced 0.05-Hz oscillations in arterial pressure in conscious dogs

1991 ◽  
Vol 260 (4) ◽  
pp. H1248-H1253 ◽  
Author(s):  
J. B. Madwed ◽  
R. J. Cohen
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Low Frequency ◽  
Respiratory Frequency ◽  
Conscious Dogs ◽  
Reflex Response ◽  
Reflex Mechanism ◽  
Effector Mechanism ◽  
Low Frequency Oscillations ◽  
Cross Correlation Analysis

We have previously reported that oscillations at 0.05 Hz can be generated by a simple computer model incorporating a negative-feedback reflex mechanism and an effector mechanism with a time delay. Computer simulations by inhibiting the vagal effector mechanism and activating the adrenergic effector mechanism elicited low-frequency oscillations at a frequency of 0.05 Hz in heart rate. We have observed that the cardiovascular system of the conscious dog, when stressed by the loss of blood, generates oscillations in arterial pressure and heart rate at a frequency of 0.05 Hz. We investigated in six conscious dogs the role of the sympathetic and parasympathetic nervous systems in generating these heart rate oscillations. During baseline conditions, the predominant peak in the arterial pressure and heart rate power spectra was located at the respiratory frequency, while the low-frequency oscillations were small. After a 30-ml/kg hemorrhage or after an 8-, 15-, or 30-ml/kg hemorrhage with glycopyrrolate, a muscarinic-blocking agent, low-frequency oscillations at a frequency of 0.05 Hz predominated, while the respiratory frequency oscillations were negligible. Since respiratory frequency oscillations have been reported to reflect vagal activity, and since the low-frequency oscillations were present after vagal blockade, these hemorrhage-induced low-frequency oscillations in heart rate may be primarily mediated by the cardiac sympathetic nerves. Also cross-correlation analysis between arterial pressure and heart rate showed that a change in arterial pressure caused an opposite change in heart rate with a delay of 2-5 s. We conclude that hemorrhage-induced oscillations in heart rate at 0.05 Hz represent the arterial baroreceptor-beta-sympathetic reflex response to underlying arterial pressure oscillations.

Comparative study on effect of neutral spinal bath and neutral spinal spray on blood pressure, heart rate and heart rate variability in healthy volunteers

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Arundhati Goley ◽  
A. Mooventhan ◽  
NK. Manjunath
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
Group Analysis ◽  
Low Frequency ◽  
Single Session ◽  
Arterial Blood ◽  
Before And After ◽  
Instantaneous Heart Rate

Abstract Background Hydrotherapeutic applications to the head and spine have shown to improve cardiovascular and autonomic functions. There is lack of study reporting the effect of either neutral spinal bath (NSB) or neutral spinal spray (NSS). Hence, the present study was conducted to evaluate and compare the effects of both NSB and NSS in healthy volunteers. Methods Thirty healthy subjects were recruited and randomized into either neutral spinal bath group (NSBG) or neutral spinal spray group (NSSG). A single session of NSB, NSS was given for 15 min to the NSBG and NSSG, respectively. Assessments were taken before and after the interventions. Results Results of this study showed a significant reduction in low-frequency (LF) to high-frequency (HF) (LF/HF) ratio of heart rate variability (HRV) spectrum in NSBG compared with NSSG (p=0.026). Within-group analysis of both NSBG and NSSG showed a significant increase in the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (HR) (RRI) (p=0.002; p=0.009, respectively), along with a significant reduction in HR (p=0.002; p=0.004, respectively). But, a significant reduction in systolic blood pressure (SBP) (p=0.037) and pulse pressure (PP) (p=0.017) was observed in NSSG, while a significant reduction in diastolic blood pressure (DBP) (p=0.008), mean arterial blood pressure (MAP) (p=0.008) and LF/HF ratio (p=0.041) was observed in NSBG. Conclusion Results of the study suggest that 15 min of both NSB and NSS might be effective in reducing HR and improving HRV. However, NSS is particularly effective in reducing SBP and PP, while NSB is particularly effective in reducing DBP and MAP along with improving sympathovagal balance in healthy volunteers.

scholarly journals Analysis of heart rate variability in corn snakes (Pantherophis guttatus)

2021 ◽  
Vol 10 (11) ◽  
pp. e294101119781
Author(s):  
Antonio Gomes da Silva Neto ◽  
Daniel Souza Ferreira Magalhães ◽  
Raduan Hage ◽  
Laurita dos Santos ◽  
José Carlos Cogo
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Low Frequency ◽  
Autonomic Nervous ◽  
Rr Interval ◽  
Diagnosis And Prognosis ◽  
Frequency Domains ◽  
The Time Domain

The assessment of heart rate variability (HRV) by linear methods in conjunction with Poincaré plots can be useful for evaluating cardiac regulation by the autonomic nervous system and for the diagnosis and prognosis of heart disease in snakes. In this report, we describe an analysis of HRV in conscious adult corn snakes Pantherophis guttatus (P. guttatus).  The electrocardiogram (ECG) parameters were determined in adult corn snakes (8 females, 13 males) and used for HRV analysis, and the RR interval was analyzed by linear methods in the time and frequency domains. There was no sex-related difference in heart rate. However, significant differences were seen in the duration of the P, PR, and T waves and QRS complex; there was no difference in the QT interval. The values for the RR interval varied by 15.3% and 18.8% in male and female snakes, respectively, and there was considerable variation in the values for the high and low frequency domains. The changes in the time domain were attributed to regulation by the parasympathetic branch of the autonomic nervous system, in agreement with variations in the high and low frequency domains. The values for standard deviations 1 and 2 in Poincaré plots, as well as the values of the frequency domain, provide useful parameters for future studies of cardiac function in P. guttatus.

scholarly journals Estimation of Delay Times in Coupling Between Autonomic Regulatory Loops of Human Heart Rate and Blood Flow Using Phase Dynamics Analysis

2017 ◽  
Vol 9 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Vladimir S Khorev ◽  
Anatoly S Karavaev ◽  
Elena E Lapsheva ◽  
Tatyana A Galushko ◽  
Mikhail D Prokhorov ◽  
...  
Keyword(s):  
Heart Rate ◽  
Delay Time ◽  
Healthy Subjects ◽  
Low Frequency ◽  
Phase Dynamics ◽  
Oscillatory Systems ◽  
Low Frequency Oscillations ◽  
Delay Times ◽  
The Difference ◽  
Regulatory Loop

Objective: We assessed the delay times in the interaction between the autonomic regulatory loop of Heart Rate Variability (HRV) and autonomic regulatory loop of photoplethysmographic waveform variability (PPGV), showing low-frequency oscillations. Material and Methods: In eight healthy subjects aged 25–30 years (3 male, 5 female), we studied at rest (in a supine position) the simultaneously recorded two-hour signals of RR intervals (RRIs) chain and finger photoplethysmogram (PPG). To extract the low-frequency components of RRIs and PPG signal, associated with the low-frequency oscillations in HRV and PPGV with a frequency of about 0.1 Hz, we filtered RRIs and PPG with a bandpass 0.05-0.15 Hz filter. We used a method for the detection of coupling between oscillatory systems, based on the construction of predictive models of instantaneous phase dynamics, for the estimation of delay times in the interaction between the studied regulatory loops. Results: Averaged value of delay time in coupling from the regulatory loop of HRV to the loop of PPGV was 0.9±0.4 seconds (mean ± standard error of the means) and averaged value of delay time in coupling from PPGV to HRV was 4.1±1.1 seconds. Conclusion: Analysis of two-hour experimental time series of healthy subjects revealed the presence of delay times in the interaction between regulatory loops of HRV and PPGV. Estimated delay time in coupling regulatory loops from HRV to PPGV was about one second or even less, while the delay time in coupling from PPGV to HRV was about several seconds. The difference in delay times is explained by the fact that PPGV to HRV response is mediated through the autonomic nervous system (baroreflex), while the HRV to PPGV response is mediated mechanically via cardiac output.

scholarly journals The state of response of autonomic nervous system in children with mitral valve prolapse

2021 ◽  
Vol 26 (4) ◽  
pp. 74-80
Author(s):  
І.О.  Mitiuriaeva-Korniyko ◽  
O.V. Kuleshov ◽  
Ya.A. Medrazhevska ◽  
L.O. Fik ◽  
T.D. Klets
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Mitral Valve ◽  
Frequency Domain ◽  
Mitral Valve Prolapse ◽  
Low Frequency ◽  
Very Low Frequency ◽  
Autonomic Nervous ◽  
Significant Difference

The article presents summarized materials on connective tissue dysplasia of the heart, primary mitral valve prolapse, dysfunction of the autonomic system. Aim of research: to estimate the condition of autonomic nervous system in children with primary mitral valve prolapse. We examined 106 children with mitral valve prolapse aged from 13 to 17 years old on the clinical base of city hospital “Center of mother and child” in Vinnitsya. Research included time and frequency domain (evaluation with cardiointervalography. Final results were compared with the control group records. The results showed no statistical significance among time domain parameters in the main group of children. All these indices displayed tendency to sympathetic and parasympathetic autonomic nervous system tonus increase in boys. However, sympathicotonia tendency was noted in girls only. Frequency domain parameters showed similar results, compared with the previous. Nevertheless, very low frequency parameters had statistically significant difference in both subgroups of patience with mitral valve prolapse, including males (3205.8±190.9 against 1717±154, р<0.05) and females (3280±220.1 against 1433±811, р<0.05). There were no statistically significant difference among other frequency domain parameters. Conclusions: we estimated that children with mitral valve prolapse have imbalanced autonomic homeostasis manifested by tone disturbances of both autonomic vegetative system branches with sympathetic predominance. Patients with primary mitral valve prolapse generally have increased sympathetic tone - both boys and girls - according to spectral analysis of heart rate variability indices, heart rate oscillation power of a very low frequency in particular (p<0.05). In children with mitral valve prolapse, the tone of parasympathetic nervous system is generally normal; there is a tendency to its increase in boys and decrease in girls. These children should be under close medical supervision by pediatricians and cardiologists.

Abstract 327: Attenuated Beta-Adrenergic Response in the Tric-a Knock Out Mice

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Yuichi Toyama ◽  
Manabu Yonekura ◽  
Chong Han ◽  
Hirofumi Tomita ◽  
Hiroshi Takeshima ◽  
...  
Keyword(s):  
Heart Rate ◽  
Action Potential ◽  
Sympathetic Nerve ◽  
Calcium Release ◽  
Calcium Influx ◽  
Ryanodine Receptors ◽  
Low Frequency ◽  
Beta Adrenergic ◽  
Knock Out ◽  
Nerve Regulation

Trimeric intracellular cation (TRIC) channels are expressed on the surface of sarcoplasmic reticulum (SR) and regulate calcium release from ryanodine receptors (RyRs). In a previous study, Tric-a knock out (KO) mice showed diminished calcium release from RyRs following increased calcium-influx via L-type calcium channels, which results in enhanced vascular resistance and non-dipper type hypertension. Decreased activation of RyR1 by PKA in skeletal myocytes in Tric-a KO mice is also known. However, physiological importance of TRIC channels on cardiac rhythm formation and its importance on the sympathetic nerve regulation are still obscure. Therefore, we aimed to clarify the effects of Tric-a ablation on cardiac pace making using Tric-a KO mice. We measured systolic blood pressure (SBP) with tail-cuff method, ECG and spontaneous action potential with microelectrode in the Tric-a KO and wild type (WT) mice. Isoproterenol or propranolol was used for sympathetic nerve manipulation. Furthermore, we evaluated heart rate variability (HRV). Tric-a KO mice tended to show limited responses to isoproterenol (0.3 mg/kg) than the WT mice (-27 ± 6 and -32 ± 6 mmHg, n = 10, p =0.70), and to propranolol (4 ± 6 and 13 ± 7 mmHg, n = 5~6, p =0.48). In ECG analysis, ablation of Tric-a gene resulted in significantly decreased heart rate changes to isoproterenol (23 ± 6 and 99 ± 15 bpm, Tric-a KO and WT mice, respectively, n = 9~10, p <0.001). Response to propranolol was also significantly decreased in the Tric-a KO mice (-28 ± 20 and -122 ± 14 bpm, Tric-a KO and WT mice, respectively, n = 9~10, p <0.001). In the action potential recordings, Tric-a KO mice showed significantly decreased sinus rate changes to 1 microM isoproterenol (35 ± 9 and 71 ± 10 bpm, Tric-a KO and WT mice, respectively, n = 6~8, p <0.05). In HRV analysis, low-frequency/high-frequency (LF/HF) ratio tended to be lower in the Tric-a KO mice than the WT mice under the administration of isoproterenol (0.22 ± 0.31 and 0.65 ± 0.16 bpm, Tric-a KO and WT mice, respectively, n = 9~11, p =0.16), suggesting lower sympathetic nerve tonus in the Tric-a KO mice. In conclusion, our data indicates that Tric-a KO mice showed attenuated responses to beta-adrenergic stimulus, which indicates involvement of TRIC-A channels in sympathetic nerve regulation.

Effect of Acupuncture on Heart Rate Variability in Primary Dysmenorrheic Women

2011 ◽  
Vol 39 (02) ◽  
pp. 243-249 ◽  
Author(s):  
Eunsook Kim ◽  
Jung-Hoon Cho ◽  
Woo Sang Jung ◽  
Sanghoon Lee ◽  
Sok Cheon Pak
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Low Frequency ◽  
Acupuncture Points ◽  
Primary Dysmenorrhea ◽  
Autonomic Nervous ◽  
Real Acupuncture ◽  
Late Luteal Phase

Primary dysmenorrhea is a common gynecological complaint among young women that is related to an autonomic nervous system (ANS) disturbance. Acupuncture is one of several therapeutic approaches for primary dysmenorrhea, since it can modulate ANS function. The heart rate variability (HRV) parameters such as high frequency (HF), low frequency (LF) and LF/HF ratio are generally accepted tools to assess ANS activity. The purpose of this study was to investigate the effects of acupuncture applied at Hegu (LI4) and Sanyinjiao (SP6) points on HRV of women with primary dysmenorrhea during the late luteal phase. The experimental design was a crossover and patient-blinded procedure. All subjects participated in Sham (SA) and Real Acupuncture (RA) procedure, separated by one month, in a crossover sequence. The participants included 38 women (mean age 22.3 years; weight 53.8 kg; height 162.6 cm). HRV measurement was 15 min before and 15 min after an acupuncture procedure. The RA procedure was performed at two bilateral acupoints, but needles were inserted subcutaneously to the acupuncture points for the SA procedure. The RA induced a significant decrease in LF/HF ratio and a significant increase in the HF power, while SA treatment caused a significant increase only in the HF power. Manual acupuncture at bilateral acupoints of LI4 and SP6 may play a role in dysmenorrhea treatment with autonomic nervous system involvement.

Paraventricular stimulation with glutamate elicits bradycardia and pituitary responses

1989 ◽  
Vol 256 (1) ◽  
pp. R112-R119 ◽  
Author(s):  
D. N. Darlington ◽  
M. Miyamoto ◽  
L. C. Keil ◽  
M. F. Dallman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Arterial Blood Pressure ◽  
Excitatory Neurotransmitter ◽  
Autonomic Nervous ◽  
Arterial Blood ◽  
Paraventricular Nuclei ◽  
Measured Activation

The excitatory neurotransmitter, L-glutamate (0.5 M, pH 7.4), or the organic acid, acetate (0.5 M, pH 7.4), was microinjected (50 nl over 2 min) directly into the paraventricular nuclei (PVN) of pentobarbital sodium-anesthetized rats while arterial blood pressure and heart rate and plasma adrenocorticotropic hormone (ACTH), vasopressin, and oxytocin were measured. Activation of PVN neurons with L-glutamate led to increases in plasma ACTH, vasopressin, and oxytocin and a profound bradycardia (approximately 80 beats/min) with little change in arterial blood pressure. Microinjection of acetate had no effect on the above variables. The decrease in heart rate was shown to be dependent on the concentration of glutamate injected and the volume of injectate. The bradycardia was mediated through the autonomic nervous system because ganglionic blockade (pentolinium tartrate) eliminated the response; atropine and propranolol severely attenuated the bradycardia. The bradycardia was greatest when L-glutamate was microinjected into the caudal PVN. Injections into the rostral PVN or into nuclei surrounding the PVN led to small or nonsignificant decreases in heart rate. Focal electric stimulation (2-50 microA) of the PVN also led to decreases in heart rate and arterial blood pressure. These data suggest that activation of PVN neurons leads to the release of ACTH, vasopressin, and oxytocin from the pituitary and a bradycardia that is mediated by the autonomic nervous system.

scholarly journals Plasma Leptin Concentrations and Cardiac Autonomic Nervous System in Healthy Subjects with Different Body Weights

2000 ◽  
Vol 85 (5) ◽  
pp. 1810-1814 ◽  
Author(s):  
Giuseppe Paolisso ◽  
Daniela Manzella ◽  
Nicola Montano ◽  
Antonio Gambardella ◽  
Michele Varricchio
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Body Fat ◽  
Total Power ◽  
Sympathovagal Balance ◽  
Arterial Blood ◽  
Fasting Plasma ◽  
Normalized Units ◽  
Plasma Leptin ◽  
Fourth Quartile

Abstract Previous studies have shown that leptin stimulates sympathetic nervous system; heart rate variability (HRV) is a widely used technique for assessing the sympathovagal balance at the cardiac level. The aim of our study was to investigate a possible relationship between plasma leptin levels and the autonomic regulation using spectral analysis of HRV. In 120 healthy nonobese subjects the plasma leptin concentration was determined, and HRV was recorded at baseline and during tilt. All subjects were categorized in quartiles of plasma leptin concentration. Analysis of data showed a significant increase in body mass index, body fat, fasting plasma insulin, triglyceride concentration, and homeostatic model assessment values throughout the different quartiles of plasma leptin concentration. Concerning cardiovascular parameters, heart rate, arterial blood pressures, and RR intervals were not significantly different among the quartiles. Total power and high frequency (HF) in normalized units were significantly decreased, whereas low frequency (LF) normalized units was progressively increased from the first to the fourth quartile. Thus, the LF/HF ratio rose gradually and significantly from the lowest to the highest quartile. Such results were independent of the body fat estimate (P &lt; 0.03 for the trend). The change in the LF/HF ratio was significantly enhanced during tilt (P &lt; 0.001 vs. rest values for all quartiles); the effect was stronger in subjects in the fourth quartile of plasma leptin concentration (P &lt; 0.005 for the trend). The latter parameter was also independent of body fat content and distribution (P &lt; 0.01). Our study shows that increasing fasting plasma leptin concentrations are associated with a shift of the sympathovagal balance toward a progressive increase in sympathetic activation and an increased response to orthostatic stimulus in nonobese subjects with different body fat contents.

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