Quantification of the Central Cardiovascular Network Applying the Normalized Short-time Partial Directed Coherence Approach in Healthy Subjects

2018 ◽  
Vol 57 (03) ◽  
pp. 129-134 ◽  
Author(s):  
Steffen Schulz ◽  
Mathias Bolz ◽  
Karl-Jürgen Bär ◽  
Andreas Voss
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Systolic Blood Pressure ◽  
Healthy Subjects ◽  
Spectral Power ◽  
Partial Directed Coherence ◽  
Regulatory Processes ◽  
The Central Nervous System ◽  
Short Time

Summary Background: The central control of the autonomic nervous system (ANS) and the complex interplay of its components can be described by a functional integrated mode – the central autonomic network (CAN). CAN represents the integrated functioning and interaction between the central nervous system (CNS) and ANS (parasympathetic and sympathetic activity). Objective: This study investigates the central cardiovascular network (CCVN) as a part of the CAN, during which heart rate (HR), systolic blood pressure (SYS) and frontal EEG activity in 21 healthy subjects (CON) will be analysed. The objective of this study is to determine how these couplings (central-cardiovascular) are composed by the different regulatory aspects of the CNS-ANS interaction. Methods: To quantify the short-term instantaneous causal couplings within the CCVN, the normalized short time partial directed coherence (NSTPDC) approach was applied. It is based on an m-dimensional MAR process to determine Granger causality in the frequency domain. Results: We found that CCVN were of bidirectional character, and that the causal influences of central activity towards HR were stronger than those towards systolic blood pressure. This suggests that the central-cardiac closed-loop regulation process in CON focuses mainly on adapting the heart rate via the sinoatrial node rather than focusing on SYS. The CNS-ANS coupling directions with respect to central spectral power bands were characterized as mostly bidirectional, where HR and SYS acted as drivers in nearly every frequency band (unidirectional for α, α1 and α2). Conclusion: This study provides a more indepth understanding of the interplay of neuronal and autonomic cardiovascular regulatory processes in healthy subjects, as well as a greater insight into the complex CAN.

scholarly journals Relation of body mass index (BMI) with cardiovascular response to head up tilt in healthy subjects

2020 ◽  
Vol 15 (1) ◽  
pp. 6-10
Author(s):  
Sadia Afrin Rimi ◽  
Shamima Sultana ◽  
Iffat Rezwana ◽  
Sultana Ferdousi
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Healthy Subjects ◽  
Cardiovascular Response ◽  
Tilt Test ◽  
Tilt Table ◽  
Chi Square ◽  
Female Head ◽  
Head Up Tilt

Background: Tilt table test is used for the last few decades to detect cause in unexplained syncope. The response to tilting may vary physiologically with obesity. Objective: To assess the relationship of BMI to cardiovascular response to tilting. Methods: This experimental study was conducted from March 2019 to Feb 2020 on 90 healthy subjects with different BMI. Fifty one subjects of both gender with BMI 18.5-24.9 kg/m2 were included in the non-obese group and 39 subjects of both gender with BMI of 25-29.9 kg/m2 were included in overweight group and they were further subdivided into male and female. Head up tilting was done for 10 minutes at 600 by using a motorized tilt table. Systolic blood pressure (SBP), diastolic blood pressure (DBP) were recorded by an automatic sphygmomanometer. Heart rate (HR) and peripheral capillary oxygen saturation (SpO2) were measured by a pulse oximeter. For statistical analysis, Independent sample ‘t’ test, Pearson’s correlation test and Chi square tests were applied. Results: Significantly smaller rise of heart rate was observed in overweight males and greater fall of systolic blood pressure was observed in overweight females. Conclusion: This study concluded that over weight is associated with reduced orthostatic tolerance to head up tilt test in both genders. J Bangladesh Soc Physiol. 2020, June; 15(1): 6-10

Intracerebroventricular infusion of RU28318 blocks aldosterone-salt hypertension

1990 ◽  
Vol 258 (3) ◽  
pp. E482-E484 ◽  
Author(s):  
E. P. Gomez-Sanchez ◽  
C. M. Fort ◽  
C. E. Gomez-Sanchez
Keyword(s):  
Blood Pressure ◽  
Central Nervous System ◽  
Nervous System ◽  
Systolic Blood Pressure ◽  
Urine Volume ◽  
Intracerebroventricular Infusion ◽  
Mineralocorticoid Antagonist ◽  
Salt Hypertension ◽  
The Central Nervous System ◽  
Dose Dependent

The chronic intracerebroventricular (icv) infusion of aldosterone in rats and dogs elevates the blood pressure within 10-14 days at doses far below those that produce hypertension systemically. The effect in rats is dose dependent and blocked by the concomitant icv infusion of the antimineralocorticoid, prorenone. The effect of the icv infusion of RU28318, another specific spironolactone mineralocorticoid antagonist, on the hypertension produced by chronic subcutaneous (sc) administration of aldosterone in sensitized rats was reported. Miniosmotic pumps were used to deliver 1 micrograms/h aldosterone sc and 1.1 micrograms/h RU8318 icv. Over a 24-day period the indirect systolic blood pressure of the control, RU28318 icv, and aldosterone sc plus RU28318 icv groups increased from 105 to 123 mmHg and were not significantly different from each other, whereas the aldosterone sc group increased to 156 mmHg. RU28318, icv or sc, did not alter the increase in urine volume produced by aldosterone sc, and there was no significant differences in weight between the groups. This study provides evidence of the importance of the central nervous system in the pathogenesis of hypertension produced by systemic mineralocorticoid excess.

scholarly journals Time-Frequency Analysis of Cardiovascular and Cardiorespiratory Interactions During Orthostatic Stress by Extended Partial Directed Coherence

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 468 ◽  
Author(s):  
Sonia Charleston-Villalobos ◽  
Sina Reulecke ◽  
Andreas Voss ◽  
Mahmood R. Azimi-Sadjadi ◽  
Ramón González-Camarena ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Information Flow ◽  
Orthostatic Intolerance ◽  
Linear Method ◽  
Orthostatic Stress ◽  
Partial Directed Coherence ◽  
Sinus Arrhythmia ◽  
Time Frequency

In this study, the linear method of extended partial directed coherence (ePDC) was applied to establish the temporal dynamic behavior of cardiovascular and cardiorespiratory interactions during orthostatic stress at a 70° head-up tilt (HUT) test on young age-matched healthy subjects and patients with orthostatic intolerance (OI), both male and female. Twenty 5-min windows were used to analyze the minute-wise progression of interactions from 5 min in a supine position (baseline, BL) until 18 min of the orthostatic phase (OP) without including pre-syncopal phases. Gender differences in controls were present in cardiorespiratory interactions during OP without compromised autonomic regulation. However in patients, analysis by ePDC revealed considerable dynamic alterations within cardiovascular and cardiorespiratory interactions over the temporal course during the HUT test. Considering the young female patients with OI, the information flow from heart rate to systolic blood pressure (mechanical modulation) was already increased before the tilt-up, the information flow from systolic blood pressure to heart rate (neural baroreflex) increased during OP, while the information flow from respiration to heart rate (respiratory sinus arrhythmia) decreased during the complete HUT test. Findings revealed impaired cardiovascular interactions in patients with orthostatic intolerance and confirmed the usefulness of ePDC for causality analysis.

Fractal Component of Variability of Heart Rate and Systolic Blood Pressure in Congestive Heart Failure

1997 ◽  
Vol 92 (6) ◽  
pp. 543-550 ◽  
Author(s):  
Gary C. Butler ◽  
Shin-Ichi Ando ◽  
John S. Floras
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Systolic Blood Pressure ◽  
Spectral Power ◽  
Normal Subjects ◽  
Total Spectral Power ◽  
Systolic Blood Pressure Variability ◽  
Harmonic Components

1. There is a substantial non-harmonic or fractal component to the variability of both heart rate and blood pressure in normal subjects. Heart rate is the more complex of these two signals, with respect to the slope, β, of the 1/fβ relationship. In congestive heart failure, heart rate spectral power is attenuated, but the fractal and harmonic components of heart rate and systolic blood pressure variability have not been characterized. 2. Two groups, each comprising 20 men, were studied during 15 min of supine rest and spontaneous respiration: one with functional class II—IV heart failure (age 52 ± 2 years; mean ± SEM) and a second group of healthy men (age 46 ± 2 years). 3. Total spectral power for heart rate was significantly reduced in heart failure (P < 0.02), whereas total spectral power for systolic blood pressure was similar in the two groups. In both heart failure and normal subjects, 65–80% of total spectral power in these two signals displayed fractal characteristics. 4. In heart failure, the slope of the 1/fβ relationship for heart rate was significantly steeper than in normal subjects (1.40 ± 0.08 compared with 1.14 ± 0.05; P < 0.05), indicating reduced complexity of the fractal component of heart rate variability. There was no significant difference in the 1/fβ slope for systolic blood pressure variability between these two groups, but the blood pressure signals were less complex than heart rate variations in both heart failure (2.31 ± 0.15; P < 0.006) and normal subjects (2.47 ± 0.15; P < 0.0001). 5. Parasympathetic nervous system activity, as estimated from heart rate variability was reduced (P < 0.01) in patients with heart failure, whereas trends towards increased sympathetic nervous system activity and decreased non-harmonic power were not significant. 6. The non-harmonic components of cardiac frequency are reduced in heart failure. Non-harmonic power is not attenuated, but the complexity of the heart rate signal is less than in subjects with normal ventricular function. A reduction in parasympathetic modulation appears to contribute to this loss of complexity of heart rate. Consequently, the heart rate signal comes to resemble that of blood pressure. In contrast, the variability and complexity of the systolic blood pressure signal is similar in heart failure and normal subjects. This reduced complexity of heart rate variability may have adverse implications for patients with heart failure.

Acute Alcohol Intake Decreases Short-Term Heart Rate Variability in Healthy Subjects

1994 ◽  
Vol 87 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Pekka Koskinen ◽  
Juha Virolainen ◽  
Markku Kupari
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Systolic Blood Pressure ◽  
High Frequency ◽  
Alcohol Intake ◽  
Spectral Power ◽  
Domain Analysis ◽  
Alcohol Concentration ◽  
High Frequency Component

1. The acute effects of a moderate dose of ethanol (1 g/kg body weight) on heart rate and blood pressure variability and baroreflex sensitivity were studied in 12 healthy male subjects in a juice-controlled experiment. Electrocardiographic and finger blood pressure data were recorded and stored in a minicomputer during 5 min of controlled breathing (15 cycles/min) and during deep breathing (5 s inpiration, 5 s expiration, four cycles) before drinking and hourly thereafter for 3 h. 2. Mean breath alcohol concentration rose to 18.9 mg/100 ml. In the time domain analysis, the root mean square difference of successive R-R interval decreased significantly with ethanol as compared with the juice experiment. The difference remained statistically significant even after adjustment for the shorter R-R interval after alcohol. In the frequency domain analysis the high-frequency (0.15-0.5 Hz) spectral power showed a significant decrease after alcohol intake. Also, the index of sensitivity of the baro-receptor reflex (square root of R-R interval power/systolic blood pressure power) decreased significantly in the high-frequency component. Ethanol did not change finger systolic blood pressure, and power spectral analysis did not show significant variability in blood pressure. 3. These data indicate that acute intake of moderate amounts of alcohol causes a significant decrease in heart rate variability owing to diminished vagal modulation of the heart rate.

scholarly journals TO STUDY THE EFFECT OF REGULAR YOGIC ACTIVITY ON THE FUNCTION OF AUTONOMIC NERVOUS SYSTEM: A COMPARATIVE STUDY.

2020 ◽  
Vol 4 (8) ◽  
Author(s):  
Abhay Choudhary ◽  
Arun Pathak ◽  
Sheela Kumari
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Systolic Blood Pressure ◽  
The Body ◽  
Relaxation Techniques ◽  
Autonomic Nervous ◽  
Hand Grip ◽  
Significant Difference

Aims: to know the influence of yoga on autonomic functions of the body. Material and Methods: The present prospective case control study was conducted among patients visited the OPD, Darbhanga Medical College and Hospital, Bihar, India. The findings were tabulated and subjected to statistical analysis. Case group (N=30): subjects who were performing regular yoga asanas and relaxation techniques for at least 5 years. Control group (N=30): age and gender matched subject who were not performing yoga asanas and relaxation techniques or were not engaged with any other type of physical exercises. Results: Amongst the sympathetic nervous system parameters, statistically significant difference existed between cases and controls for the Resting Heart Rate, Resting Diastolic Blood Pressure, Hand grip systolic blood pressure and Hand grip systolic blood pressure (p<0.05) respectively. Conclusion: yogic activity significantly alters the sympathetic activity like heart rate and blood pressure. Keywords: Autonomic Nervous system, Yoga, Heart Rate, Blood Pressure

scholarly journals Cardiovascular response to strength training is more affected by intensity than volume in healthy subjects

2018 ◽  
Vol 11 (3) ◽  
Author(s):  
OC Moreira ◽  
CEP Oliveira ◽  
DG Matos ◽  
SF Silva ◽  
RC Hickner ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Resistance Exercise ◽  
Systolic Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Healthy Subjects ◽  
Bench Press ◽  
Cardiovascular Response ◽  
Rate Pressure Product ◽  
Repetition Maximum

Objective: To determine and compare the cardiovascular responses to three resistance exercise protocols with different volumes and loads. Methods: The study included 15 healthy subjects, experienced in resistance training, who underwent supine bench press exercise with three different volumes and loads separated by 48 hours, with a crossover model: a) 4 repetitions at 90% of one repetition maximum (4/90%), b) 8 repetitions at 80% of one repetition maximum (8/80%), and c) 15 repetitions at 65% of one repetition maximum (15/65%). Immediately following each protocol, measures of heart rate, systolic and diastolic blood pressure were performed, and were used to calculate the rate pressure product. Results: The 4/90% protocol resulted in an increase in heart rate (Δ = 84.57%; effect size [ES] = 0.31), systolic blood pressure (Δ = 24.03%; ES = 0.42), diastolic blood pressure (Δ = 8.47%; ES = 0.27) and rate pressure product (Δ = 129.65%; ES = 0.54). The 8/80% protocol resulted in changes on: heart rate (Δ = 74.94%; ES = 0.57), systolic blood pressure (Δ = 20.67%; ES = 0.27), diastolic blood pressure (Δ = 6.91%; ES = 0.15) and rate pressure product (Δ = 111.78%; ES = 0.48). The 15/65% protocol resulted in alterations on: heart rate (Δ = 66.77%; ES = 0.39), systolic blood pressure (Δ = 16.85%; ES = 0.35), diastolic blood pressure (Δ = 3.38%; ES = 0.13) and rate pressure product (Δ = 96.41%; ES = 0.30). Increases in all variables pre to post resistance exercise were observed for all protocols (p < 0.05). When comparing the three different protocols, it was found that the heart rate (p < 0.001), systolic blood pressure (p = 0.034) and rate pressure product (p < 0.001), were more elevated in the 4/90% compared to the 15/65%. Conclusion: The bench press exercise performed with low volume and high intensity promotes a more pronounced cardiovascular response compared to the same exercise performed with high volume and low intensity.      

P4388Acute detrimental effects of e-cigarette and tobacco cigarette smoking on blood pressure and sympathetic nerve activity in healthy subjects

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
K Dimitriadis ◽  
C Tsioufis ◽  
K Kontantinou ◽  
I Liatakis ◽  
E Andrikou ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Cigarette Smoking ◽  
Sympathetic Nerve ◽  
Healthy Subjects ◽  
Sympathetic Nerve Activity ◽  
Nerve Activity ◽  
Tobacco Cigarette ◽  
Sympathetic Nervous

Abstract Background/Introduction Tobacco cigarette smoking is related with atherosclerosis progression, blood pressure increase and changes in sympathetic nerve activity. However, there are scarce data on the impact of e-cigarettes that have been proposed as less harmful alternatives on the cardiovascular system and sympathetic drive. Purpose This study aimed to assess the acute effects of tobacco cigarettes, e-cigarettes and sham smoking on blood pressure and sympathetic nervous system in healthy subjects. Methods We studied 10 normotensive male habitual smokers (mean age 33 years, body mass index: 24.1 kg/m2, office blood pressure=117/72 mmHg) free of cardiovascular disease. The study design was randomized and placebo controlled with 3 experimental sessions (sham smoking, tobacco cigarette smoking, and e-cigarette smoking) in random order, each session on a separate day. Subjects smoked 2 tobacco cigarettes containing 1.1 mg nicotine or simulate smoking (sham smoking) with the 2 cigarettes separated by 5 minutes, while 45 minutes after finishing the second cigarette, subjects smoked a third cigarette or sham cigarette. Additionally, participants smoked e-cigarettes for a period of 5 and 30 minutes. In all occasions, sympathetic drive was assessed by muscle sympathetic nerve activity (MSNA) (baroreflex-dependent) and skin sympathetic nerve activity (SSNA) (baroreflex-independent) based on established methodology (microneurography). Results After the first, second and third tobacco cigarette smoking there was markedly and significantly increase in mean arterial pressure (by 11.2±1.4%, 12.3±1.3% and 13.1±1.4%, respectively, p<0.05 for all) and heart rate (by 25.1±3.7%, 26.3±2.7% and 25.9±3.7%, respectively, p<0.05 for all). Similarly e-cigarette smoking at 5 and 30 minutes was accompanied by augmentation of mean arterial pressure (by 10.9±1.2% and 12.8±1.4%, respectively, p<0.05 for both) and heart rate (by 22.5±3.3% and 23.9±3.8%, respectively, p<0.05 for both). Regarding the effect on sympathetic nervous system, the first, second and third tobacco cigarette smoking was accompanied by lower MSNA (by 28.1±4.4%, 29.6±5.3% and 30.1±5.2%, respectively, p<0.05 for all), whereas SSNA was increased (by 98.2±19.4%, 100.2±22.7% and 101.5±21.6%, respectively, p<0.05 for all). Additionally, e-cigarette smoking at 5 and 30 minutes caused a decrease in MSNA (by 26.9±3.6%, and 28.3±5.1%, respectively, p<0.05 for both), and an augmentation in SSNA (by 97.9±20.1% and 100.9±20.6%, respectively, p<0.05 for both). Sham smoking was devoid of any effects on blood pressure, MSNA and SSNA. Conclusions E-cigarette smoking acutely increases blood pressure and has a detrimental effect on sympathetic nerve activity regulation similar to tobacco smoking in healthy subjects. Our findings underscore the negative impact of e-cigarettes on cardiovascular and autonomic nervous system and could aid further recommendation in their use.

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