scholarly journals Cooling-Evoked Hemodynamic Perturbations Facilitate Sympathetic Activity with Subsequent Myogenic Vascular Oscillations via Alpha2-Adrenergic Receptors

2017 ◽  
pp. 449-457 ◽  
Author(s):  
Y.-H. LIN ◽  
Y.-P. LIU ◽  
Y.-C. LIN ◽  
P.-L. LEE ◽  
C.-S. TUNG
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pressor Response ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Sprague Dawley ◽  
Cold Stimulation ◽  
Very Low Frequency ◽  
Power Spectral ◽  
Sprague Dawley Rats

This study extends our previous work by examining the effects of alpha2-adrenoceptors under cold stimulation involving the increase of myogenic vascular oscillations as increases of very-low-frequency and low-frequency of the blood pressure variability. Forty-eight adult male Sprague-Dawley rats were randomly divided into four groups: vehicle; yohimbine; hexamethonium+yohimbine; guanethidine+yohimbine. Systolic blood pressure, heart rate, power spectral analysis of spontaneous blood pressure and heart rate variability and spectral coherence at very-low-frequency (0.02 to 0.2 Hz), low-frequency (0.2 to 0.6 Hz), and high-frequency (0.6 to 3.0 Hz) regions were monitored using telemetry. Key findings are as follows: 1) Cooling-induced pressor response was attenuated by yohimbine and further attenuated by hexamethonium+yohimbine and guanethidine+yohimbine, 2) Cooling-induced tachycardia response of yohimbine was attenuated by hexame-thonium+yohimbine and guanethidine+yohimbine, 3) Different patterns of power spectrum reaction and coherence value compared hexamethonium+yohimbine and guanethi-dine+yohimbine to yohimbine alone under cold stimulation. The results suggest that sympathetic activation of the postsynaptic alpha2-adrenoceptors causes vasoconstriction and heightening myogenic vascular oscillations, in turn, may increase blood flow to prevent tissue damage under stressful cooling challenge.

Impact of Changes in Respiratory Frequency and Posture on Power Spectral Analysis of Heart Rate and Systolic Blood Pressure Variability in Normal Subjects and Patients with Heart Failure

1996 ◽  
Vol 91 (1) ◽  
pp. 35-43 ◽  
Author(s):  
John E. Sanderson ◽  
Leata Y. C. Yeung ◽  
Dickens T. K. Yeung ◽  
Richard L. C. Kay ◽  
Brian Tomlinson ◽  
...  
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Heart Rate ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Normal Subjects ◽  
Power Spectral ◽  
Patients With Heart Failure

1. Autonomic dysfunction is a major feature of congestive cardiac failure and may have an important role in determining progression and prognosis. The low-frequency/high-frequency ratio derived from power spectral analysis of heart rate variability has been proposed as a non-invasive method to assess sympatho-vagal balance. However, the effects of different respiratory rates or posture are rarely accounted for, but may be relevant in patients with heart failure in whom clinical improvement is accompanied by a fall in respiratory rate and an increased proportion of the day in the upright position. 2. We have assessed the effect of controlled respiration at different rates (10, 15, 20 breaths/min or 0.17, 0.25 and 0.33 Hz), while supine and standing, on power spectral analysis of heart rate and blood pressure variability in 11 patients with heart failure and 10 normal subjects. 3. Heart rate variance and low-frequency power (normalized units) were reduced in patients with heart failure (absent in six). During controlled breathing while supine, the power of the high-frequency component was significantly greater at 10 breaths/min than at 20 breaths/min in patients with heart failure, whether expressed in absolute units (P = 0.005) or percentage of total power (P = 0.03). 4. On standing, controlled breathing in patients with heart failure produced less change in high-frequency power (P = 0.054), but the low-frequency/high-frequency ratio at lower respiratory rates was reduced (P = 0.05). In normal subjects, as expected, respiratory rate had a highly significant effect on high-frequency power. Also, in normal subjects there was the expected increase in heart rate low-frequency power (P = 0.04) moving from supine to standing with an increase in the low-frequency/high-frequency ratio (P = 0.003), while in the patients with heart failure this was absent, reflecting blunted cardiovascular reflexes. 5. Systolic blood pressure low- and high-frequency components and their ratio were significantly affected by respiration (P > 0.03) and change in posture (P > 0.03) in both patients with heart failure and normal subjects, with a significant increase in the low-frequency/high-frequency ratio (P = 0.03) on standing in patients with heart failure, indicating that autonomic modulation of blood pressure is still operating in heart failure. 6. Thus, respiratory rate and changes in posture have a significant effect on measurements derived from spectral analysis of heart rate and blood pressure variability. Studies that use power spectral analysis as a measure of sympatho-vagal balance should control for these variables.

scholarly journals Power spectral analysis of heart rate variability in Bangladeshi healthy male and female

2016 ◽  
Vol 43 (3) ◽  
pp. 146-150
Author(s):  
Qazi Farzana Akhter ◽  
Qazi Shamima Akhter ◽  
Farhana Rahman ◽  
Sybilla Ferdousi ◽  
Susmita Sinha
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Autonomic Nerve ◽  
Age Group ◽  
Power Spectral

Heart rate variability (HRV) has been considered as an indicator of autonomic nerve function status. We aimed to find out the reference values of heart rate variability by power spectral analysis in our healthy population of both sex. This cross sectional study was conducted in the Department of Physiology, Dhaka Medical College, Dhaka from the period of July 2012 to June 2013. For this, 180 subjects were selected with the age ranging from 15-60 years. All the study subjects were divided into 3 different groups according to age (Group A: 15-30 years; Group B: 31-45 years; Group C: 46-60 years). Each group contained 60 subjects of which 30 were male and 30 were female. Analysis of HRV parameters were done in Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka. Systolic blood pressure, diastolic blood pressure, low frequency normalized unit, low frequency / high frequency ratio were significantly higher in male than female. Again high frequency power, high frequency normalized unit were significantly higher in female than male of same age group. This study concludes that male showed higher cardiac sympathetic activities while female showed higher cardiac parasympathetic activities in different age groups.Bangladesh Med J. 2014 Sep; 43 (3): 146-150

Power spectral analysis of heart rate and blood pressure variability in anaesthetized dogs

1992 ◽  
Vol 146 (2) ◽  
pp. 155-164 ◽  
Author(s):  
A. E. HEDMAN ◽  
J. E. K. HARTIKAINEN ◽  
K. U. O. TAHVANAINEN ◽  
M. O. K. HAKUMÄKI
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spectral Analysis ◽  
Blood Pressure Variability ◽  
Power Spectral Analysis ◽  
Power Spectral

Dynamics of spectral components of heart rate variability during changes in autonomic balance

1998 ◽  
Vol 275 (1) ◽  
pp. H213-H219 ◽  
Author(s):  
Michael V. Højgaard ◽  
Niels-Henrik Holstein-Rathlou ◽  
Erik Agner ◽  
Jørgen K. Kanters
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Supine Position ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Frequency Domain Analysis ◽  
Autonomic Balance ◽  
Power Spectral ◽  
Normalized Units ◽  
Semiquantitative Method

Frequency domain analysis of heart rate variability (HRV) has been proposed as a semiquantitative method for assessing activities in the autonomic nervous system. We examined whether absolute powers, normalized powers, and the low frequency-to-high frequency ratio (LF/HF) derived from the HRV power spectrum could detect shifts in autonomic balance in a setting with low sympathetic nervous tone. Healthy subjects were examined for 3 h in the supine position during 1) control conditions ( n = 12), 2) acute β-blockade ( n = 11), and 3) chronic β-blockade ( n = 10). Heart rate fell during the first 40 min of the control session (72 ± 2 to 64 ± 2 beats/min; P < 0.005) and was even lower during acute and chronic β-blockade (56 ± 2 beats/min; P < 0.005). The powers of all spectral areas rose during the first 60 min in all three settings, more so with β-blockade ( P < 0.05). LF/HF was found to contain the same information as powers expressed in normalized units. LF/HF detected the shift in autonomic balance induced by β-blockade but not the change induced by supine position. In conclusion, none of the investigated measures derived from power spectral analysis comprehensively and consistently described the changes in autonomic balance.

scholarly journals Power Spectral Analysis of Spontaneous Blood Pressure and Heart Rate Variability in Elderly Hypertensives.

1996 ◽  
Vol 19 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Tadashi Aono ◽  
Takayuki Sato ◽  
Masanori Nishinaga ◽  
Akiko Kawamoto ◽  
Toshio Ozawa
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Power Spectral Analysis ◽  
Power Spectral ◽  
Elderly Hypertensives

Abnormal passive head-up tilt test in subjects with symptoms of anxiety power spectral analysis study of heart rate and blood pressure

1997 ◽  
Vol 60 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Gianfranco Piccirillo ◽  
Santagada Elvira ◽  
Carmela Bucca ◽  
Emanuela Viola ◽  
Mauro Cacciafesta ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spectral Analysis ◽  
Power Spectral Analysis ◽  
Tilt Test ◽  
Analysis Study ◽  
Power Spectral ◽  
Head Up Tilt ◽  
Head Up Tilt Test

Power Spectral Analysis of Heart Rate and Diastolic Blood Pressure Variability in Migraine with and Without Aura

Cephalalgia ◽  
1997 ◽  
Vol 17 (7) ◽  
pp. 756-760 ◽  
Author(s):  
G Pierangeli ◽  
P Parchi ◽  
G Barletta ◽  
M Chiogna ◽  
E Lugaresi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spectral Analysis ◽  
Diastolic Blood Pressure ◽  
Blood Pressure Variability ◽  
Power Spectral Analysis ◽  
Cardiovascular Responses ◽  
Valsalva Manoeuvre ◽  
Cardiovascular Reflexes ◽  
Power Spectral

Autonomic function in migraineurs during headache-free periods was studied by means of cardiovascular reflexes and power spectral analysis of heart rate and diastolic blood pressure variability. We examined 56 patients: 37 suffering from migraine without aura and 19 from migraine with aura. Cardiovascular responses to the tilt test and Valsalva manoeuvre showed a normal function of the overall baroreceptor reflex arc. Normal heart rate responses to valsalva manoeuvre and deep breathing suggested an intact parasympathetic function. Power spectral analysis of both heart rate and diastolic blood pressure variability in basal conditions and during orthostatic test showed similar sympathovagal interactions modulating cardiovascular control in migraine patients and in controls.

A STANDARDIZED METHOD FOR THE PRODUCTION OF HEMORRHAGIC SHOCK IN THE RAT

1955 ◽  
Vol 33 (3) ◽  
pp. 436-447 ◽  
Author(s):  
H. G. Downie ◽  
J. A. F. Stevenson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mortality Rate ◽  
Hemorrhagic Shock ◽  
Respiratory Rate ◽  
Rectal Temperature ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Standardized Method

Although the blood pressure is one of the important criteria in the standardization of hemorrhagic shock in the dog, it has rarely been used for this purpose in the rat. A method resembling the reservoir technique developed by Wiggers and Werle (1942) for the dog using blood pressure as the criterion has been modified for use with the rat. Male Sprague-Dawley rats weighing approximately 400 gm. were used. In the standardization of this technique the blood pressure was reduced to 30 mm. Hg in a 10-min. period of hemorrhage and then maintained at this level by subsequent small hemorrhages into the reservoir until reinfusion indicated the beginning of vascular collapse, at which time all the blood in the reservoir was returned. Considering that those animals which lived longer than 48 hr. were survivors, in a series of 27 animals, 21 died and 6 survived—a mortality rate of 78%.During the hypotensive period there was a consistent and steady drop in the respiratory rate and rectal temperature. The heart rate declined initially and tended to recover as the hypotensive period progressed. After reinfusion the blood pressure rose but. did not reach prehemorrhage levels. Hemorrhage into the bowel and convulsions were significant postreinfusion findings.

Effect of provocative maneuvers on heart rate variability in subjects with quadriplegia

1995 ◽  
Vol 268 (6) ◽  
pp. H2239-H2245 ◽  
Author(s):  
D. R. Grimm ◽  
R. E. DeMeersman ◽  
R. P. Garofano ◽  
A. M. Spungen ◽  
W. A. Bauman
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Sympathetic Activity ◽  
Spectral Component ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Parasympathetic Activity ◽  
Power Spectral ◽  
Spectral Components ◽  
Male Subjects

This study investigated heart rate variability (HRV) in individuals with quadriplegia who have disruption of autonomic control of the heart. Seven male subjects with neurological complete quadriplegia and seven with incomplete quadriplegia were studied at rest and during provocation. HRV was measured by power spectral analysis using a fast Fourier transform. Two spectral components were generated: 1) the high-frequency (HF) peak, a reflection of parasympathetic activity, and 2) the low-frequency (LF) peak, primarily sympathetic activity with some parasympathetic input. Results of the provocative maneuvers were grouped into one composite variable. Significant differences in the LF spectral component were found between the groups with complete and incomplete lesions in the supine position and after provocation (LF supine: P = 0.01; LF provocation: P = 0.002). After provocation, significant differences were demonstrated in the HF spectral component between these groups (P = 0.005). In contrast to previous findings, a LF component in subjects with complete quadriplegia was observed; this LF component decreased after provocation, suggesting the parasympathetic component withdrew during stressful maneuvers. There also appeared to be general downregulation of parasympathetic activity to the heart in subjects with complete quadriplegia. The presence of an increased LF spectral component during provocation in those with incomplete lesions implies sympathetic stimulation of the heart and may be used as a marker of sympathetic activity in individuals with quadriplegia.

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