Heart rate as a determinant of the decay rate of the cardiac inotropic response to sympathetic nervous activity

1983 ◽  
Vol 61 (11) ◽  
pp. 1374-1381 ◽  
Author(s):  
Yukitaka Masuda ◽  
Matthew N. Levy
Keyword(s):  
Heart Rate ◽  
Sinus Rhythm ◽  
Nervous Activity ◽  
Ventricular Myocardium ◽  
Sympathetic Nervous Activity ◽  
Inotropic Response ◽  
Sympathetic Stimulation ◽  
Junctional Rhythm ◽  
Decay Times ◽  
Inotropic Responses

The cardiac responses to sympathetic nerve stimulation were measured in a series of open-chest, anesthetized dogs. In half the animals, the hearts were in a sinus rhythm; in the remaining animals, the hearts were in an atrioventricular (AV) junctional rhythm. Cocaine markedly prolonged the decay times of the chronotropic responses after cessation of sympathetic stimulation, regardless of the type of rhythm. The decay times of the inotropic responses were only slightly prolonged by cocaine in animals with a sinus rhythm, but the prolongations were pronounced in animals with an AV junctional rhythm. The lower basal heart rate appeared to be more responsible for the greater decay times of the inotropic responses in the animals with an AV junctional rhythm than in those with a sinus rhythm. In a second series of dogs, complete heart block was produced, cocaine was given, AND the hearts were paced at four different frequencies. The mean decay time of the inotropic response to sympathetic stimulation varied inversely AND substantially with the pacing frequency. The change in contraction frequency probably affects the rate of neurotransmitter dissipation from the ventricular myocardium, by altering either the coronary blood flow or the massaging action of the cardiac contractions.

Increased heart rate accelerates norepinephrine washout from normal myocardium

1987 ◽  
Vol 253 (6) ◽  
pp. H1581-H1585 ◽  
Author(s):  
R. J. Henning ◽  
J. Cheng ◽  
A. M. Bhat ◽  
M. N. Levy
Keyword(s):  
Heart Rate ◽  
Ventricular Myocardium ◽  
Neuronal Uptake ◽  
Control Group ◽  
Inotropic Response ◽  
Sympathetic Stimulation ◽  
Uptake Mechanism ◽  
The Mean ◽  
Time Required ◽  
Experimental Group

We determined whether a change in heart rate affected the decay of the ventricular inotropic response to sympathetic stimulation in an experimental group and in a control group of anesthetized dogs. We induced complete heart block in each animal and paced the ventricles at rates of 90, 120, and 150 min-1 during two observation periods. In the experimental group, desipramine hydrochloride was given during the second period to block the neuronal uptake mechanism. The control animals did not receive desipramine during either period. The time required for the ventricular inotropic response to decay by 50% after cessation of a 2-min train of sympathetic stimulation was used as an index of the rate of norepinephrine washout from the myocardial interstitium. As we increased the pacing rate over the range of 90-150 min-1 in the experimental group, the mean decay half times (+/- SE) decreased by 36 +/- 4% (P less than 0.001) before desipramine and by 26 +/- 6% (P less than 0.001) in the presence of desipramine. These decrements in the decay half times were not significantly different from each other. The mean decay half times decreased by 36 +/- 4% (P less than 0.001) in the control dogs; the effects did not change appreciably from the first to the second observation period. We conclude that an increase in pacing frequency facilitates the washout of norepinephrine from the ventricular myocardium; this facilitation is equally pronounced regardless of whether the neuronal uptake mechanism is intact or suppressed.

Heart Rate Variability During Early Mobilization in Patients with Acute Ischemic Stroke

2018 ◽  
Vol 80 (1-2) ◽  
pp. 50-54 ◽  
Author(s):  
Masafumi Nozoe ◽  
Miho Yamamoto ◽  
Miki Kobayashi ◽  
Masashi Kanai ◽  
Hiroki Kubo ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Nervous Activity ◽  
Early Mobilization ◽  
Sympathetic Nervous Activity ◽  
Parasympathetic Nerve ◽  
Significant Difference ◽  
Sympathetic Nervous

Autonomic dysfunction is one of the predictors of poor outcome in patients with acute ischemic stroke. We compared the heart rate variability (HRV) during early mobilization in patients with or without neurological deterioration (ND). We enrolled 7 acute ischemic patients with ND and 14 without ND and measured their HRV in the rest and mobilization by electrocardiography. There was a significant difference in sympathetic nervous activity during mobilization between the 2 groups. However, no significant differences in blood pressure, heart rate, and parasympathetic nerve activity were observed. In patients with acute ischemic stroke, it is likely that the increase in sympathetic nervous activity during mobilization is associated with ND.

463 The Effect of Intervention of Medical Staff on the Adherence of CPAP and Heart Rate in Patients with Obstructive Sleep Apnea

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A182-A183
Author(s):  
Ryutaro Shirahama ◽  
Rie Ishimaru ◽  
Jun Takagiwa ◽  
Yasue Mitsukura
Keyword(s):  
Heart Rate ◽  
Medical Staff ◽  
Nervous Activity ◽  
Sympathetic Nervous Activity ◽  
Sleep Stages ◽  
Obstructive Sleep ◽  
Group A ◽  
Group B ◽  
Tele Monitoring ◽  
Mean Heart Rate

Abstract Introduction Recent studies have indicated that obstructive sleep apnea syndrome (OSAS) is associated with hypertension. OSA is a common cause of sympathetic nervous activity. Increase of sympathetic nervous activity causes hypertension. Continuous positive airway pressure (CPAP) is the most useful treatment for OSAS. Good CPAP adherence treatment improve the risk of hypertension. This study examined the effect of intervention of medical staff on the adherence of CPAP, heart rate and sleep stages in patients with OSA. Methods All patients diagnosed with OSA and undergoing subsequent CPAP were clinically followed for 12 months to examine CPAP adherence, as well as longitudinal changes in blood pressure, average heartrate of 24 hours and sleep stages. They were divided into 2 groups, Group A: patients who had individual consulted in person by sleep physician and technicians before start using CPAP and Group B: patents who did not have individual consulted. Patients in both groups were consulted by sleep physician and technicians after start CPAP with utilizing tele-monitoring. If the adherence were poor, the patients were recommended to stop CPAP. We provided 3D accelerometer and an optical pulse photoplethysmography to all the patients and analyzed the data of heart rate and sleep stages. Results A total of 30 OSA patients underwent CPAP, were enrolled in the study and assessed for changes in mean heart rate and body weight during the study period. We found a significant reduction in mean heart rate in both group A and B compared with baseline (p<-0.05). The patients aged under 50 years old and whose AHI<20 times/hour have higher ratio of dropout CPAP therapy. There was no significant difference between Group A and Group B on the persistency rate of CPAP therapy. Also, no significant association was found between group A and B on the adherence of CPAP. Conclusion We showed the importance of the effect of intervention of medical staff on the adherence of CPAP and heart rate in patients with OSA the consultation after starting CPAP for a while with utilizing tele-monitoring data would be more effective compared with that in person before start using CPAP. Support (if any):

scholarly journals Large potassium shifts during dialysis enhance cardiac repolarization instability

2020 ◽  
Author(s):  
Dominik Schüttler ◽  
Ulf Schönermarck ◽  
Felix Wenner ◽  
Marcell Toepfer ◽  
Konstantinos D. Rizas ◽  
...  
Keyword(s):  
Nervous Activity ◽  
Ventricular Myocardium ◽  
Sympathetic Nervous Activity ◽  
Clear Correlation ◽  
The Novel ◽  
Fluid Removal ◽  
Non Invasive ◽  
End Stage ◽  
Present Pilot Study ◽  
Malignant Arrhythmias

Abstract Background Patients with end-stage kidney disease are at high risk for the development of arrhythmias and sudden cardiac death (SCD). This has been especially attributed to large potassium shifts during hemodialysis (HD), and malignant arrhythmias are closely linked to dysfunction of the autonomic nervous system. Nevertheless, there is still a lack of methods for risk stratification in these patients. Methods In the present pilot study we investigated changes of the novel ECG-based biomarker periodic repolarization dynamics (PRD) mirroring the effect of efferent sympathetic nervous activity on the ventricular myocardium in 18 patients undergoing routine hemodialysis. High-resolution ECGs were recorded throughout the dialysis and PRD values were calculated out of 30 min intervals at the start and the end of dialysis. Results We detected a clear correlation between the intradialytic potassium shift and the increase in PRD levels (Spearman correlation coefficient R = 0.62, p = 0.006). Patients with a potassium shift > 1 mmol/l showed significantly increased levels of PRD at the end of dialysis when compared to patients with potassium shifts ≤ 1.0 mmol/l [delta PRD 2.82 (IQR 2.13) vs. − 2.08 (IQR 3.60), p = 0.006]. Spearman analysis showed no significant correlation between PRD changes and fluid removal (R = − 0.23, p = 0.36). Conclusions We provide evidence that large potassium shifts during HD enhance sympathetic activity-associated repolarization instability. This could facilitate the occurrence of malignant arrhythmias, and PRD measurements might serve as a non-invasive monitoring tool in HD patients in future.

Hypoxemia raises muscle sympathetic activity but not norepinephrine in resting humans

1989 ◽  
Vol 66 (4) ◽  
pp. 1736-1743 ◽  
Author(s):  
L. B. Rowell ◽  
D. G. Johnson ◽  
P. B. Chase ◽  
K. A. Comess ◽  
D. R. Seals
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous Activity ◽  
Plasma Concentrations ◽  
Random Order ◽  
Sympathetic Nervous Activity ◽  
Severe Hypoxemia ◽  
Arterial Blood ◽  
End Tidal ◽  
Venous Plasma

The experimental objective was to determine whether moderate to severe hypoxemia increases skeletal muscle sympathetic nervous activity (MSNA) in resting humans without increasing venous plasma concentrations of norepinephrine (NE) and epinephrine (E). In nine healthy subjects (20–34 yr), we measured MSNA (peroneal nerve), venous plasma levels of NE and E, arterial blood pressure, heart rate, and end-tidal O2 and CO2 before (control) and during breathing of 1) 12% O2 for 20 min, 2) 10% O2 for 20 min, and 3) 8% O2 for 10 min--in random order. MSNA increased above control in five, six, and all nine subjects during 12, 10, and 8% O2, respectively (P less than 0.01), but only after delays of 12 (12% O2) and 4 min (8 and 10% O2). MSNA (total activity) rose 83 +/- 20, 260 +/- 146, and 298 +/- 109% (SE) above control by the final minute of breathing 12, 10, and 8% O2, respectively. NE did not rise above control at any level of hypoxemia; E rose slightly (P less than 0.05) at one time only with both 10 and 8% O2. Individual changes in MSNA during hypoxemia were unrelated to elevations in heart rate or decrements in blood pressure and end-tidal CO2--neither of which always fell. We conclude that in contrast to some other sympathoexcitatory stimuli such as exercise or cold stress, moderate to severe hypoxemia increases leg MSNA without raising plasma NE in resting humans.

Inhibition of renal sympathetic nervous activity by area postrema stimulation in rabbits

1987 ◽  
Vol 253 (1) ◽  
pp. H91-H99 ◽  
Author(s):  
E. M. Hasser ◽  
D. O. Nelson ◽  
J. R. Haywood ◽  
V. S. Bishop
Keyword(s):  
Heart Rate ◽  
Electrical Stimulation ◽  
Arterial Pressure ◽  
Nucleus Tractus Solitarius ◽  
Area Postrema ◽  
Nervous Activity ◽  
Sympathetic Nervous Activity ◽  
Consistent Change ◽  
Renal Sympathetic ◽  
Stimulation Of

This study investigated the effect of chemical and electrical stimulation of the area postrema on renal sympathetic nerve activity (RSNA), arterial pressure, and heart rate in urethan-anesthetized rabbits. Electrical stimulation of the area postrema at 2, 5, 10, 20, 40, and 80 Hz using constant currents of 7.5, 15, and 30 microA (pulse duration = 0.3 ms, train duration = 5 s) produced progressive decreases in RSNA and heart rate, with no consistent change in arterial pressure. To control for electrical activation of fibers of passage in or near the area postrema, L-glutamate was injected into the area postrema using glass micropipettes. Micropressure injection of L-glutamate (10 mM) in volumes of 5-10 nl produced rapid decreases in RSNA averaging 27 +/- 5% (P less than 0.05) accompanied by a small bradycardia. The effects of electrical stimulation of the area postrema, but not the adjacent nucleus tractus solitarius, were totally eliminated by micropressure injection of kainic acid (40 ng in 40 nl) into the area postrema. During continuous electrical stimulation of the area postrema using parameters that produced small decrements in RSNA and heart rate, the slope of the line relating baroreflex inhibition of RSNA to increases in arterial pressure during graded infusions of phenylephrine was significantly enhanced (-6.77 +/- 1.30 vs. -3.81 +/- 0.66% RSNA/mmHg). These data are consistent with the hypothesis that activation of neurons in the area postrema results in an inhibition of RSNA. Furthermore, stimulation of the area postrema augments baroreflex inhibition of RSNA during increases in arterial pressure with phenylephrine.

scholarly journals Effects of Walking in a Forest on Young Women

2019 ◽  
Vol 16 (2) ◽  
pp. 229 ◽  
Author(s):  
Chorong Song ◽  
Harumi Ikei ◽  
Takahide Kagawa ◽  
Yoshifumi Miyazaki
Keyword(s):  
Heart Rate ◽  
Young Women ◽  
Physiological Responses ◽  
Nervous Activity ◽  
Differential Method ◽  
Sympathetic Nervous Activity ◽  
Relaxation Effects ◽  
Subjective Evaluations ◽  
Total Mood Disturbance ◽  
Negative Feelings

The effects of forest activities on health promotion have received increasing attention. The aim of this study was to evaluate the physiological and psychological effects of brief walks in forests on young women. The experiments were conducted in 6 forests (test) and 6 city areas (control). Overall, 12 participants in each area (60 participants in total, mean age: 21.0 ± 1.3 years) were instructed to walk in a forest and a city area for approximately 15 min; simultaneously, their heart rate variability, heart rate, blood pressure, and pulse rate were measured to quantify their physiological responses to walking. The modified semantic differential method, Profile of Mood States (POMS), and the State–Trait Anxiety Inventory (STAI) were used to determine their psychological responses. Walking in a forest was associated with significantly higher parasympathetic nervous activity and lower sympathetic nervous activity and heart rate. In addition, scores for the comfortable, relaxed, and natural parameters and vigor subscale of POMS were significantly higher, whereas scores for negative feelings, such as tension–anxiety, depression–dejection, anger–hostility, fatigue, and confusion, were significantly lower, as were the total mood disturbance of POMS and the anxiety dimension of the STAI. The subjective evaluations were generally in accordance with the physiological responses. A brief walk in a forest resulted in physiological and psychological relaxation effects in young women.

scholarly journals Heart failure switches the RV α1-adrenergic inotropic response from negative to positive

2010 ◽  
Vol 298 (3) ◽  
pp. H913-H920 ◽  
Author(s):  
Guan-Ying Wang ◽  
Che-Chung Yeh ◽  
Brian C. Jensen ◽  
Michael J. Mann ◽  
Paul C. Simpson ◽  
...  
Keyword(s):  
Heart Failure ◽  
Clinical Problem ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Coronary Artery Ligation ◽  
Inotropic Response ◽  
Artery Ligation ◽  
Protein Levels ◽  
Inotropic Responses

Right ventricular (RV) failure is a serious common clinical problem that is poorly understood. Therefore, for failing and nonfailing hearts, we examined the distinctive inotropic responses induced in the RV myocardium after the stimulation of α1-adrenergic receptors (ARs). In RV trabeculae from nonfailing mouse hearts, α1-ARs induced a negative inotropic response, consistent with our previous study. In marked contrast, in RV trabeculae from failing hearts, 12 wk after coronary artery ligation, α1-ARs induced a positive inotropic response. Mechanistically, experiments with skinned trabeculae showed that α1-ARs decreased myofilament Ca2+ sensitivity in the nonfailing RV myocardium, whereas α1-ARs increased Ca2+ sensitivity in heart failure. This suggests that a switch in the Ca2+ sensitivity response to α1-AR stimulation explained the switch in the RV α1-AR inotropic response in heart failure. Myosin light chain kinase (MLCK) can increase myofilament Ca2+ sensitivity, and the smooth muscle isoform (smMLCK), which is also present in cardiomyocytes, was more abundant in the RV myocardium from failing versus nonfailing hearts. Moreover, the MLCK inhibitor ML-9 prevented the switch of the RV myocardium to a positive α1-AR inotropic response in heart failure. In the left ventricular myocardium, in contrast, α1-AR inotropic responses were not different in failing versus nonfailing hearts, and smMLCK abundance was not increased in heart failure. In relation to human disease, we found that smMLCK mRNA and protein levels were increased in RVs from failing human hearts. We conclude that the RV inotropic response to α1-ARs is switched from negative to positive in heart failure, through a pathway involving increased myofilament Ca2+ sensitivity. Since α1-AR agonist catecholamines are elevated in heart failure, increased α1-AR inotropic responses in the RV myocardium may be adaptive in heart failure by helping the failing RV respond to increased pulmonary pressures.

Intradermal Acupuncture on Shen-Men and Nei-Kuan Acupoints Improves Insomnia in Stroke Patients by Reducing the Sympathetic Nervous Activity: A Randomized Clinical Trial

2009 ◽  
Vol 37 (06) ◽  
pp. 1013-1021 ◽  
Author(s):  
Seung Yeop Lee ◽  
Yong Hyeon Baek ◽  
Seong Uk Park ◽  
Sang Kwan Moon ◽  
Jung Mi Park ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Controlled Trial ◽  
Nervous Activity ◽  
Sham Acupuncture ◽  
Acupuncture Group ◽  
Sympathetic Nervous Activity ◽  
Stroke Patients ◽  
Double Blind ◽  
Intradermal Acupuncture

This study is a double-blind randomized controlled trial on the effect of intradermal acupuncture on insomnia after stroke. Hospitalized stroke patients with insomnia were enrolled in the study and were randomly assigned to either a real intradermal acupuncture group (RA group) or a sham acupuncture group (SA group). The RA group received intradermal acupuncture on Shen-Men (He-7) and Nei-Kuan (EH-6) for three days, and the SA group received sham acupuncture on the same points. The effect of acupuncture on insomnia was measured using Insomnia Severity Index (ISI) and Athens Insomnia Scale (AIS) at baseline and three days after treatment. To assess the effect of acupuncture on the autonomic nervous function, the subjects' blood pressure and heart rate variability were monitored. Fifty-two subjects (27 in the RA group and 25 in the SA group) were included in the final analysis. The insomnia-related scales ISI and AIS showed greater improvement of insomnia in the RA group than in the SA group. Moreover, there is a greater reduction of the number of non-dippers and a greater decrease of the LF/HF ratio (heart rate variability) in the RA group than in the SA group. These results indicate that sympathetic hyperactivities were stabilized in the RA group. It can thus be concluded that intradermal acupuncture on Shen-Men and Nei-Kuan is a useful therapeutic method for post stroke-onset insomnia as it reduces sympathetic hyperactivities.

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