Heart rate variability responses to hypoxic and hypercapnic exposures in different mouse strains

2005 ◽  
Vol 99 (3) ◽  
pp. 807-813 ◽  
Author(s):  
Matthew J. Campen ◽  
Yugo Tagaito ◽  
Todd P. Jenkins ◽  
Alex Balbir ◽  
Christopher P. O’Donnell
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Inbred Mice ◽  
Strain Differences ◽  
Cardiovascular Responses ◽  
Mouse Strains ◽  
Cardiac Autonomic Nervous System ◽  
Arterial Blood

Heart rate variability (HRV) is a well-characterized, noninvasive means of assessing cardiac autonomic nervous system activity. This study examines the basic cardiac responses to hypoxic and hypercapnic challenges in seven strains of commonly used inbred mice (A/J, BALB/cJ, C3H/HeJ, C57BL/6J, CBA/J, DBA/2J, and FVB/J). Adult male mice, 8–12 wk of age, were chronically instrumented to a femoral artery catheter for the continuous measurement of systemic arterial blood pressure and heart rate. Mice were exposed to multiple 4-min periods of hypoxia (10% O2), hypercapnia (5% CO2), and combined hypoxia/hypercapnia (10% O2 + 5% CO2). HRV was derived from pulse intervals of the blood pressure tracings. Hypoxia induced increases in high-frequency HRV power and decreased low-frequency (LF) HRV power in most strains. Hypercapnia led to decreased high-frequency HRV power and increased LF HRV power in most strains. Strain differences were most notable in regard to the concomitant exposures of hypoxia and hypercapnia, with FVB/J mice mirroring their own response to hypercapnia alone, whereas CBA/J mice mirrored their own responses to hypoxia. As blood pressure is most likely the driving factor for heart rate changes via the baroreflex pathway, it is interesting that LF, considered to reflect cardiac sympathetic activity, was negatively correlated with heart rate, suggesting that LF changes are driven by baroreflex oscillation and not necessarily by absolute sympathetic or parasympathetic activity to the heart. These findings suggest that genetic background can influence the centrally mediated cardiovascular responses to basic hypoxic and hypercapnic challenges.

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.

Ascending pathways mediating somatoautonomic reflexes in exercising dogs

1987 ◽  
Vol 62 (3) ◽  
pp. 1186-1191 ◽  
Author(s):  
J. W. Kozelka ◽  
G. W. Christy ◽  
R. D. Wurster
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Surgical Techniques ◽  
Arterial Occlusion ◽  
Cardiovascular Responses ◽  
Spinal Pathways ◽  
Arterial Blood ◽  
Bilateral Carotid ◽  
Dorsolateral Funiculus ◽  
Carotid Arterial

The ascending spinal pathways mediating somatocardiovascular reflexes during exercise were studied in unanesthetized dogs by placing lesions in the lumbar spinal cord. After training to run on a treadmill with hindlimbs only, 20 dogs were anesthetized and instrumented using sterile surgical techniques. To chronically record heart rate and arterial blood pressure, the aorta was cannulated via the omocervical artery. To test the intactness of descending spinal sympathetic pathways, reflex pressor responses to baroreceptor hypotension were produced by bilateral carotid arterial occlusion using pneumatic vessel occluders placed around the common carotid arteries. To generate transient ischemic exercise (120 s), a pneumatic occluder was placed around the left iliac artery. Eight to 10 days after instrumentation, blood pressure and heart rate were monitored at rest and during hindlimb running with and without simultaneous iliac arterial occlusion. The modest pressor response and tachycardia elicited by hindlimb exercise were markedly augmented by simultaneous hindlimb ischemia (i.e., iliac arterial occlusion). Lesion placement in the dorsolateral sulcus area and the dorsolateral funiculus at L2 significantly reduced the blood pressure and heart rate responses to simultaneous exercise occlusion. The cardiovascular responses to nonischemic exercise and bilateral carotid arterial occlusion were not altered by such spinal sections. It is concluded that in the dog the ascending spinal pathways mediating cardiovascular responses to ischemic exercise are located in the lateral funiculus, including the dorsolateral sulcus area and dorsolateral funiculus.

Interactions between brain acetylcholine and prostaglandins in control of vasopressin release

1991 ◽  
Vol 261 (2) ◽  
pp. R420-R426
Author(s):  
M. Inoue ◽  
J. T. Crofton ◽  
L. Share
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Cardiovascular Responses ◽  
Vasopressin Release ◽  
Arterial Blood ◽  
Plasma Vasopressin ◽  
Vasopressin Secretion ◽  
Stimulation Of

We have examined in conscious rats the interaction between centrally acting prostanoids and acetylcholine in the stimulation of vasopressin secretion. The intracerebroventricular (icv) administration of carbachol (25 ng) resulted in marked transient increases in the plasma vasopressin concentration and mean arterial blood pressure and a transient reduction in heart rate. Central cyclooxygenase blockade by pretreatment icv with either meclofenamate (100 micrograms) or indomethacin (100 micrograms) virtually completely blocked these responses. Prostaglandin (PG) D2 (20 micrograms icv) caused transient increases in the plasma vasopressin concentration (much smaller than after carbachol) and heart rate, whereas mean arterial blood pressure rose gradually during the 15-min course of the experiment. Pretreatment with the muscarinic antagonist atropine (10 micrograms icv) decreased the peak vasopressin response to icv PGD2 by approximately one-third but had no effect on the cardiovascular responses. We conclude that the stimulation of vasopressin release by centrally acting acetylcholine is dependent on increased prostanoid biosynthesis. On the other hand, stimulation of vasopressin release by icv PGD2 is partially dependent on activation of a cholinergic pathway.

Cardiovascular responses to severe hypercapnia of short duration

1964 ◽  
Vol 207 (3) ◽  
pp. 634-640 ◽  
Author(s):  
Emmett S. Manley ◽  
Clinton B. Nash ◽  
R. A. Woodbury
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Short Duration ◽  
Cardiovascular Responses ◽  
Myocardial Contraction ◽  
Contractile Force ◽  
Sympathetic Activation ◽  
Pentobarbital Anesthesia ◽  
Arterial Blood ◽  
Blood Ph

Dogs under pentobarbital anesthesia were employed in an investigation of the effect of abrupt, severe hypercapnia upon blood pressure, heart rate, and force of myocardial contraction. Electrocardiographic activity and arterial blood pH were also monitored. Hypercapnia was induced for 10-min periods with 15 and 30% CO2 in oxygen. The studies were undertaken in nontreated animals and animals treated with atropine, reserpine, chlorisondamine, P-286, or bilateral adrenalectomy. Severe hypercapnia was shown to be depressant to the cardiovascular parameters evaluated, but blood pressure and contractile force normally demonstrated compensation to this depression. Parasympathetic blockade with atropine did not reduce the depression observed in the nontreated dogs during hypercapnia. Results obtained with other pretreated animals indicate that compensation occurs primarily via sympathetic activation. Adrenal activation may assume importance in compensation to 30% CO2, but intact adrenals were not necessary for survival during hypercapnia. No arrhythmias (excluding bradycardia) were observed during or immediately following exposure to either concentration of CO2.

Spectral Analysis of Systolic Blood Pressure and Heart Rate after Heart Transplantation in Children

1995 ◽  
Vol 88 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Isabelle Constant ◽  
Arlette Girard ◽  
Jérôme Le Bidois ◽  
Elizabeth Villain ◽  
Dominique Laude ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Heart Transplantation ◽  
Systolic Blood Pressure ◽  
High Frequency ◽  
Power Spectra ◽  
Critical Factor ◽  
Group B ◽  
Cardiac Afferents

1. The aim of the study was to examine the short-term variability in blood pressure and heart rate in 19 children who had received heart transplants and in eight normal control children. 2. Blood pressure was determined by a finger arterial pressure device. We examined the power spectra for heart rate and systolic blood pressure in the supine and tilted positions. In addition, we studied the acute changes in blood pressure and heart rate during active standing. 3. In the transplanted children we could distinguish two groups (groups A and B) in whom heart rate variability differed, although in both it was greatly reduced compared with controls (group C). In group A there were no significant fluctuations in the mid-frequency range for heart rate. The gain of the relationship between systolic blood pressure and heart rate was very low and there were virtually no heart rate changes associated with passive tilting. 4. By contrast, in group B transplant patients the heart rate variability, as assessed by standard deviation, was about half that of normal controls. The power spectra attenuation was greater in the high-frequency than in the mid-frequency bands. On passive tilting the latter became enhanced, but not the high-frequency variability. On active standing the tachycardic response was about half that of controls. The findings suggest some reinnervation involving cardiac sympathetic fibres to a greater degree than the fast-responding vagal fibres. 5. In both groups A and B the drop in systolic blood pressure observed early in active standing was about 4–6 times as great as in controls. One possible mechanism could be the loss of cardiac afferents. 6. Time since operation was a critical factor for reinnervation, since all subjects from group B were transplanted more than 44 months prior to the recording. 7. We conclude that in a proportion of children who have received heart transplantation there is a delayed reinnervation of the heart, which probably involves sympathetic effectors rather than the vagus.

Measurement Of Bradykinin-Induced Venous Dilation By Ultrasound And Correlation With Heart Rate, Arterial And Venous Pressure And Endothelial Damage

1981 ◽  
Author(s):  
G J Stewart ◽  
R G Schaub ◽  
R E Cartee
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood Pressure ◽  
Carotid Arteries ◽  
Jugular Vein ◽  
Venous Pressure ◽  
Cardiovascular Responses ◽  
Endothelial Damage ◽  
Whole Body ◽  
Arterial Blood

This study was done to correlate known cardiovascular responses to bradykinin (increased heart rate, lowered arterial blood pressure) with recently demonstrated endothelial damage and proposed venous dilation. Healthy dogs of mixed breed were used. Blood pressures and heart rate were monitored and recorded on a Narco physiograph. The diameter of a jugular vein was monitored with an ADR ultrasound machine using a 10 MHz probe with linear array of crystals and recorded on polaroid prints. Jugular veins and carotid arteries were removed and prepared for scanning electron microscopy after removal of blood and partial in situ fixation by whole body perfusion. The response of arterial pressure was dose dependent with no change at 6 ug/min, variable drop at 12 ug/min and 22-40% drop at 60 ug/min and above. Venous pressure increased in 1 dog but was unchanged in 4 others. The increase of heart rate paralled the drop in arterial blood pressure. The diameter of a jugular vein increased in 3 of 3 monitored dogs by 25, 33, 50% of baseline diameter (average increase 36%) with high (300 ug/min) bradykinin. Endothelial damage (microtears) occurred around 70-80% of branches, at some valves and on the main vessel occassionally. The tears were infiltrated with leukocytes and some red cells and platelets indicating that tearing occurred while blood was still circulating, i.e. before dissection for removal of vessels. Carotid arteries showed no tears. Dilation of arteries would be limited by their elastic layers (missing in veins). These observations show that venous dilation and endothelial tearing around side branches are part of the cardiovascular response to blood born bradykinin. They also show that venous dilation can be measured by ultrasound.

Integrating behavior and cardiovascular responses: posture and locomotion. I. Static analysis

1993 ◽  
Vol 265 (6) ◽  
pp. R1458-R1468 ◽  
Author(s):  
O. A. Smith ◽  
C. A. Astley ◽  
F. A. Spelman ◽  
E. V. Golanov ◽  
V. G. Chalyan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Computer Control ◽  
Cardiovascular Responses ◽  
Papio Hamadryas ◽  
Code Generator ◽  
Frequency Distributions ◽  
Arterial Blood ◽  
Free Ranging

Heart rate, arterial blood pressure, and renal and mesenteric or femoral blood flow were telemetered from 11 Papio hamadryas in an untethered free-ranging situation. The animals' behavior was recorded on videotape, and the cardiovascular (CV) data were recorded on the audio channels of the tape. The behavior was coded, and the codes were linked to the CV data via a time-code generator and computer control. The CV data were digitized into 1-s intervals, and the static relations between CV measures and the postures/locomotions (P/Ls) associated with the behavior were analyzed. The total frequency distributions for heart rate, blood pressure, and renal conductance approximated Gaussian distributions, whereas femoral conductance was positively skewed. The distribution for renal conductance suggested that during normal waking conditions the kidney is not maximally dilated and may increase or decrease its blood flow. All distributions were highly influenced by the Sit category, which occupied 80% of the total time. The CV measures for all P/Ls had wide ranges, and the CV values associated with each P/L overlapped those for the other P/Ls. The heart rate and renal conductance associated with the various P/Ls showed the largest deviations from the grand means and therefore contributed the most to the ability to discriminate one P/L from another. Blood pressure varied little from one P/L to another. The patterns of CV variables served to distinguish particular P/Ls very effectively. The frequency distributions were separated best when they were parceled on the basis of the intensity of behavior associated with a particular P/L. These variations in intensity were the major cause of the overlaps in the frequency distributions associated with P/Ls.

Identification of low and high frequency ranges for heart rate variability and blood pressure variability analyses using pharmacological autonomic blockade with atropine and propranolol in swine

2011 ◽  
Vol 103 (2) ◽  
pp. 188-196 ◽  
Author(s):  
Rosangela Poletto ◽  
Andrew M. Janczak ◽  
Ruth M. Marchant-Forde ◽  
Jeremy N. Marchant-Forde ◽  
Donald L. Matthews ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Blood Pressure Variability ◽  
Autonomic Blockade

scholarly journals Effect of moderate physical exercises on the relationship of variability of the heart rhythm with the level of blood pressure and hemodynamic functions in women with essential hypertension

2020 ◽  
pp. 64-73
Author(s):  
Б.И. Кузник ◽  
Ю.Н. Смоляков ◽  
Е.С. Гусева ◽  
С.О. Давыдов ◽  
И.В. Файн
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Heart Rate Variability ◽  
Essential Hypertension ◽  
High Frequency ◽  
Low Frequency ◽  
Mean Square ◽  
Positive Correlations ◽  
The Relationship

Цель исследования - выявление взаимосвязи между показателями вариабельности сердечного ритма (ВСР), кровяным давлением и гемодинамическими функциями у женщин, страдающих гипертонической болезнью (ГБ) и находящихся на медикаментозной терапии (ГБ-1), либо в дополнение к этому, проходящих регулярные курсы кинезитерапии (ГБ-2). Методика. Наблюдения проведены на 72 женщинах, страдающих артериальной гипертензией II стадии. В группу ГБ-1 вошли 37 женщин с ГБ, находящихся на медикаментозной терапии, в группу ГБ-2 - 35 женщин с ГБ, которые, помимо медикаментозной терапии, регулярно проходили на протяжении 2-3 лет по 3-4 полуторамесячных курса кинезитерапии (управляемые умеренные физические нагрузки). Для изучения гемодинамики был использован датчик динамического рассеяния света (miniature Dynamic Light Scattering - mDLS) от Elfi-Tech (Rehovot, Israel), измеряющий сигналы, инициированные кожным кровотоком, и использующий методику разложения сигнала на частотные компоненты, связанные с разными гемодинамическими источниками. Из пульсовой компоненты mDLS сигнала извлекалась информация о вариабельности RR-интервалов и рассчитывались индикаторы вариабельности сердечного ритма. Введен показатель «гемодинамический индекс» (Hemodynamic Index - HI). Зависимость HI от скорости сдвига интерпретируется путем сопоставления каждой полосе частот определенной скорости сдвига (HI1 - низкочастотный, HI2 - промежуточный, HI3 - высокочастотный). Использованы следующие относительные (RHI, Relative Hemodynamic Index) и осцилляторные (OHI, Oscillatory Hemodynamic Indexes) гемодинамические индексы: нейрологический (NEUR), Майера (MAYER), дыхательный (RESP) и пульсовой (PULSE). ВСР показатели включали: HR (Heart Rate), PWR (Power) - общую мощность колебаний, LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences), а также индексы: CVI (Cardiac Vagal Index) и CSI (Cardiac Sympathetic Index). Результаты. У женщин, находящихся исключительно на медикаментозной терапии (ГБ-1), выявляются отрицательные взаимосвязи LF и LF/HF с систолическим, средним и пульсовым давлением. При ГБ-2 проявляются отрицательные связи PWR, LF, HF с пульсовым давлением. При ГБ-1 обнаружены положительные взаимосвязи между HR и гемодинамическими индексами HI1, RHI2 и отрицательная взаимосвязь с RHI3, а также между RMSSD и RHI3 и между HF и HI1/HI3. У пациенток ГБ-2 обнаружена отрицательная корреляция SDNN и RHI1, а также PWR и RHI1; положительные взаимосвязи между PWR и HI2, HI3, RHI2, HF и RHI3 и LF/HF с HI1/HI3; отрицательные связи HF c HI1/HI3 и с RHI1, а также между LF/HF и RHI3, CSI и RHI3. У больных ГБ-1 имеются прямые связи между SDNN, PWR, LF, HF, CVI и NEUR_HI1, что свидетельствует о действии этих факторов на эндотелиальный кровоток (HI1). В группе ГБ-2 установлено наличие лишь положительных связей между LF, HF и NEUR_HI3. У больных ГБ-1 на уровень АД влияют все без исключения осцилляторные ритмы, которые могут оказывать как отрицательное (с MAYER_HI1, PULSE_HI2), так и положительное (MAYER_HI2, RESP_HI3) влияние. У больных ГБ-2 взаимосвязи АД с осцилляторными индексами не обнаружены. Заключение. Уменьшение в группе ГБ-2 по сравнению с больными группы ГБ-1 числа факторов, влияющих на АД и гемодинамику, носит более совершенный и благоприятный характер, что и обеспечивает более быструю и устойчивую нормализацию артериального давления. Aim. To study the relationship between heart rate variability (HRV), blood pressure and hemodynamic functions in women with essential hypertension (EH) receiving a drug therapy alone (EH-1) or in combination with regular courses of kinesitherapy (EH-2). Methods. The study included 72 women with EH. The EH-1 group consisted of 37 women with stage II arterial hypertension. The EH-2 group consisted of 35 women with stage II arterial hypertension who underwent 3-4 1.5-month courses of kinesitherapy (controlled moderate physical activity) on a regular basis for 2-3 years. Hemodynamics was studied with a miniature Dynamic Light Scattering (mDLS) sensor from Elfi-Tech (Rehovot, Israel), which measures signals initiated by the skin blood flow by decomposing the signal into frequency components associated with different hemodynamic sources. Information on the RR interval variability was extracted from the pulse component of mDLS signal, and indicators of heart rate variability were calculated. A Hemodynamic Index (HI) was introduced. The HI dependence on shear rate was interpreted by matching each frequency band with a specific shear rate (HI1, low-frequency; HI2, intermediate; HI3, high-frequency). The following relative (RHI, Relative Hemodynamic Index) and oscillatory (OHI, Oscillatory Hemodynamic Indexes) indexes were used: neurological (NEUR), Mayer (MAYER), respiratory (RESP), and pulse (PULSE) ones. The HRV indexes included HR (Heart Rate), PWR (Power, total oscillation power), LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences). CVI (Cardiac Vagal Index), and CSI (Cardiac Sympathetic Index). Results. In women who were on drug therapy alone (EH-1), negative relationships were found for LF and LF/HF with systolic, mean and pulse pressure. For EH-2, PWR, LF, and HF negatively correlated with pulse pressure. For EH-1, HR positively correlated with the hemodynamic indices HI1 and RHI2 and negatively correlated with RHI3; RMSSD negatively correlated with RHI3; and HF negatively correlated with HI1/HI3. For patients with EH-2, negative correlations were observed for SDNN and RHI1, PWR and RHI1; positive correlations were found between PWR and HI2; HI3, RHI2, HF and RHI3; and between LF/HF and HI1/HI3. HF negatively correlated with HI1/HI3 and with RHI1. LF/HF negatively correlated with RHI3, and CSI negatively correlated with RHI3. In patients with EH-1, SDNN, PWR, LF, HF, CVI, and NEUR_HI1 were directly related, which indicated an effect of these factors on the endothelial blood flow (HI1). In the EH-2 group, only positive correlations were found between LF, HF, and NEUR_HI3. In EH-1 patients, all oscillatory rhythms influenced BP; this influence could be both negative (for MAYER_HI1, PULSE_HI2) and positive (for MAYER_HI2, RESP_HI3). In EH-2 patients, no relationship was found between blood pressure and oscillatory indices. Conclusion. The smaller number of factors influencing blood pressure and hemodynamics in the EH-2 group compared to the EH-1 group was more beneficial and favorable, which ensured faster and steadier normalization of blood pressure.

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