scholarly journals Changes in Respiratory Rate, Blood Pressure and Heart Rate Variability in Rabbits during Orthostasis

2006 ◽  
Vol 75 (1) ◽  
pp. 3-12 ◽  
Author(s):  
J. Mokrý ◽  
T. Remeňová ◽  
K. Javorka
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Respiratory Rate ◽  
Supine Position ◽  
Spectral Power ◽  
Systemic Blood Pressure ◽  
Microcomputer System ◽  
Systemic Blood ◽  
Frequency Bands

The purpose of the study was to evaluate the changes of respiratory rate, systemic blood pressure and heart rate variability parameters (HRV) during orthostasis in anaesthetized rabbits. Furthermore, these changes were influenced by affecting the renin-angiotensin-aldosterone (RAA) system and autonomic nervous system (ANS) to study the mechanisms participating in activity of spectral frequency bands of HRV in rabbits. Ten adult rabbits (Chinchilla) were anaesthetized by ketamine and flunitrazepam. The systemic blood pressure, tidal volume and respiratory rate were measured. HRV was evaluated by microcomputer system VariaPulse TF3E. The R-R intervals were derived from the electrocardiogram signal from subcutaneous needle electrodes. The evaluation of HRV in very low (VLF; 0.01-0.05 Hz), low (LF; 0.05-0.15 Hz) and high frequency bands (HF; 0.15-2.0 Hz) was made and parameters of frequency and time analysis were calculated. The measurements were made in horizontal (supine) position, in orthostasis (the angle of 60 °) and again in supine position before and after enalapril (0.5 mg/kg b.w.), metipranolol (0.2 mg/kg b.w.), and after subsequent bilateral cervical vagotomy. The orthostasis in anaesthetized rabbits is accompanied by depression of respiratory rate reversed only by vagotomy. Furthermore, decrease of systemic blood pressure, unchanged heart rate and increased characteristics of heart rate variability were found, with predominant increase of spectral power in LF and VLF bands. This elevation can be eliminated only by complete blockade of ANS. Although the participation of ANS or RAA system in modification of individual HRV frequency bands is not as specific as in humans, we confirmed the participation of RAA system in determination of the VLF band.

Neural mechanism underlying basilar arterial constriction by intracisternal L-NNA in anesthetized dogs

1993 ◽  
Vol 265 (1) ◽  
pp. H103-H107 ◽  
Author(s):  
N. Toda ◽  
K. Ayajiki ◽  
T. Okamura
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cerebral Arteries ◽  
Neural Mechanism ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Anesthetized Dogs ◽  
Arterial Constriction ◽  
Synthase Inhibitor

Basilar arterial diameters were angiographically measured in anesthetized dogs in which systemic blood pressure and heart rate were also monitored. Injections of NG-nitro-L-arginine (L-NNA), a NO synthase inhibitor, into the cisterna magna produced a significant, persistent decrease in arterial diameter, the effect being reversed by intracisternal injections of L-arginine. The vasoconstrictor effect of L-NNA was diminished in dogs treated with hexamethonium. On the other hand, treatment with phentolamine in a dose sufficient to lower blood pressure to a level similar to that attained with hexamethonium did not inhibit, but rather potentiated, the effect of intracisternal L-NNA. Nicotine injected into the vertebral artery significantly dilated the basilar artery. The effect was abolished by treatment with L-NNA applied intracisternally, the inhibition being reversed by the addition of L-arginine. Systemic blood pressure and heart rate were not altered by intracisternally applied L-NNA and L-arginine. These findings support the hypothesis that basilar arterial constriction caused by intracisternal L-NNA is associated with a suppression of NO synthesis in nitroxidergic nerves innervating the cerebroarterial wall rather than an elimination of basal release of NO from the endothelium. Functional importance of nitroxidergic vasodilator innervation in cerebral arteries in vivo is thus clarified.

Baroreceptor influence on postural changes in blood pressure and carotid blood flow

1963 ◽  
Vol 205 (2) ◽  
pp. 360-364 ◽  
Author(s):  
Francis L. Abel ◽  
John H. Pierce ◽  
Warren G. Guntheroth
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Sinus ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Carotid Blood Flow ◽  
Postural Changes ◽  
Nembutal Anesthesia

The effects of 30° head-down and head-up tilting on mean systemic blood pressure, carotid blood flow, and heart rate were studied in 16 dogs under morphine and Nembutal anesthesia. The tilting procedure was further repeated after denervation of the carotid sinus and aortic arch baroreceptors and after administration of a dihydrogenated ergot alkaloid mixture (Hydergine). The results indicate that the drop in pressure in the head-down position is primarily due to baroreceptor activity and that the baroreceptors are necessary for compensatory vasoconstriction on head-up tilting. Carotid blood flow decreased in both tilted positions in the control animals; the possible relationship to cerebral blood flow is discussed.

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.

scholarly journals The Effect of Live Spontaneous Harp Music on Patients in the Intensive Care Unit

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ann Marie Chiasson ◽  
Ann Linda Baldwin ◽  
Carrol Mclaughlin ◽  
Paula Cook ◽  
Gulshan Sethi
Keyword(s):  
Blood Pressure ◽  
Intensive Care Unit ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Intensive Care ◽  
Oxygen Saturation ◽  
Respiratory Rate ◽  
Rest Period ◽  
Underlying Mechanism ◽  
To Receive

This study was performed to investigate the effect of live, spontaneous harp music on individual patients in an intensive care unit (ICU), either pre- or postoperatively. The purpose was to determine whether this intervention would serve as a relaxation or healing modality, as evidenced by the effect on patient’s pain, heart rate, respiratory rate, blood pressure, oxygen saturation, and heart rate variability. Each consenting patient was randomly assigned to receive either a live 10-minute concert of spontaneous music played by an expert harpist or a 10-minute rest period. Spontaneous harp music significantly decreased patient perception of pain by 27% but did not significantly affect heart rate, respiratory rate, oxygen saturation, blood pressure, or heart rate variability. Trends emerged, although being not statistically significant, that systolic blood pressure increased while heart rate variability decreased. These findings may invoke patient engagement, as opposed to relaxation, as the underlying mechanism of the decrease in the patients’ pain and of the healing benefit that arises from the relationship between healer, healing modality, and patient.

scholarly journals PROGNOSTIC VALUE OF HEART RATE AND SYSTEMIC BLOOD PRESSURE IN PULMONARY ARTERIAL HYPERTENSION

2010 ◽  
Vol 55 (10) ◽  
pp. A154.E1443
Author(s):  
Malcolm M. Bersohn ◽  
Shelley Shapiro ◽  
Michelle P. Turner ◽  
Glenna Traiger ◽  
Adaani E. Frost
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Prognostic Value ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Pulmonary Arterial

P504 HEMODYNAMIC RESPONSE TO NON-SELECTIVE BETA BLOCKERS DESPITE LACK OF EFFECTS ON HEART RATE AND SYSTEMIC BLOOD PRESSURE

2014 ◽  
Vol 60 (1) ◽  
pp. S237
Author(s):  
S. Bota ◽  
M. Mandorfer ◽  
P. Schwabl ◽  
P. Salzl ◽  
A. Ferlitsch ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Beta Blockers ◽  
Systemic Blood Pressure ◽  
Hemodynamic Response ◽  
Systemic Blood

Influence of Sympatholytic Drugs on the Cardiovascular Response to Isometric Exercise

1981 ◽  
Vol 60 (2) ◽  
pp. 139-143 ◽  
Author(s):  
S. J. Watt ◽  
R. D. Thomas ◽  
P. W. Belfield ◽  
P. W. Goldstraw ◽  
S. H. Taylor
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Healthy Subjects ◽  
Cardiovascular Response ◽  
Pressor Response ◽  
Isometric Exercise ◽  
Systemic Blood Pressure ◽  
Isometric Handgrip ◽  
Systemic Blood ◽  
Oral Doses

1. The effects of single oral doses of various sympatholytic drugs on the heart rate and blood pressure increases during isometric handgrip contraction were studied in six healthy subjects. 2. Bethanidine reduced both the systolic and diastolic increases in pressure. Clonidine reduced the systolic but not the diastolic increase. Oxprenolol alone or in combination with phentolamine or phenyoxybenzamine failed to influence the pressor response. 3. The increase in systemic blood pressure associated with sustained contraction of voluntary muscle appears to be relatively resistant to acute sympathetic adrenoreceptor blockade in man.

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.

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