Disparities in circulatory adjustment to standing between young and elderly subjects explained by pulse contour analysis

1992 ◽  
Vol 83 (2) ◽  
pp. 149-155 ◽  
Author(s):  
W. Wieling ◽  
D. P. Veerman ◽  
J. H. A. Dambrink ◽  
B. P. M. Imholz
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Total Peripheral Resistance ◽  
Age Groups ◽  
Peripheral Resistance ◽  
The Elderly ◽  
Pulse Contour ◽  
Elderly Subjects ◽  
Orthostatic Stress ◽  
Young Subjects

1. The circulatory adjustment to standing was investigated in two age groups. Young subjects consisted of 20 healthy 10–14-year-old girls and boys. Elderly subjects consisted of 40 70–86-year-old healthy and active females and males. Continuous responses of blood pressure and heart rate were recorded by Finapres. A pulse contour algorithm applied to the finger arterial pressure waveform was used to assess stroke volume responses. 2. During the first 30 s (initial phase), an almost identical drop in mean blood pressure was found in both age groups (young, 16 ± 10 mmHg; old, 17 ± 10 mmHg), but the initial heart rate increase was attenuated in the elderly subjects (young, 29 ± 7 beats/min; old, 17 ± 7 beats/min). 3. During the period from 30 s to 10 min of standing, mean blood pressure increased from 96 ± 12 to 106 ± 12 mmHg in the elderly subjects compared with almost no change in the young subjects (from 82 ± 8 to 84 ± 7 mmHg). In the elderly subjects a progressive increase in total peripheral resistance (from 114 ± 14% to 146 ± 29%) was found, compared with an initial rapid increase in total peripheral resistance (126 ± 18% after 30 s) with no further change during prolonged standing (124 ± 17% after 10 min) in the young subjects. In this age group the decrease in stroke volume and the increase in heart rate after 10 min of standing were large (young, −37 ± 11% and 27 ± 11 beats/min; old, −31 ± 9% and 7 ± 6 beats/min, respectively). 4. In conclusion, young subjects adjust to orthostatic stress mainly by a marked increase in heart rate. In healthy elderly subjects an attenuation of the heart rate response during orthostatic stress is compensated by a pronounced increase in total peripheral resistance resulting in an increase in blood pressure.

Effect of ‘Autonomic Blockade’ on Cardiac β-Adrenergic Chronotropic Responsiveness in Healthy Young, Healthy Elderly and Endurance-Trained Elderly Subjects

1994 ◽  
Vol 87 (3) ◽  
pp. 297-302 ◽  
Author(s):  
G. A. Ford ◽  
O. F. W. James
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Geometric Mean ◽  
Cardiovascular Responses ◽  
The Elderly ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Autonomic Blockade ◽  
Young Subjects

1. Cardiac chronotropic responses to isoprenaline are reduced with ageing in man. It is unclear whether this is due to reduced cardiac β-adrenergic sensitivity or to age-associated differences in reflex cardiovascular responses to the vasodilatory effects of isoprenaline. Age-associated changes in physical activity are also reported to influence β-adrenergic sensitivity. 2. The aim of the present study was to determine the contribution of alterations in reflex changes in parasympathetic and sympathetic influences and physical fitness to the age-associated reduction in cardiac chronotropic responses to β-adrenergic agonists. 3. The effect of ‘autonomic blockade’ with atropine (40 μg/kg intravenously) and clonidine (4 μg/kg intravenously) on blood pressure, heart rate and chronotropic responses to intravenous bolus isoprenaline doses was determined in eight healthy young (mean age 21 years), nine healthy elderly (72 years) and 10 endurance-trained elderly (69 years) subjects. 4. Elderly subjects had a reduced increase in heart rate after atropine (young, 49 ± 9 beats/min; elderly, 36 ± 5 beats/min; endurance-trained elderly, 34 ± 12 beats/min; P < 0.01) and did not demonstrate the transient increase in systolic blood pressure after clonidine observed in young subjects (young, 11 ± 10 mmHg; elderly, −12 ± 16 mmHg; endurance-trained elderly, −18 ± 11 mmHg; P < 0.01). 5. Cardiac chronotropic sensitivity to isoprenaline after ‘autonomic blockade’ increased in the young but decreased in the elderly subjects. The isoprenaline dose that increased heart rate by 25 beats/min before and after autonomic blockade' was: young, before 1.6 μg, after 2.8 μg, P < 0.01 (geometric mean, paired test); elderly, before 6.9 μg, after 3.6 μg, P < 0.05; endurance-trained elderly, before 5.9 μg, after 4.0 μg, P < 0.05. Cardiac chronotropic sensitivity to isoprenaline was significantly reduced in elderly compared with young subjects before (P < 0.01) but was similar after (P = 0.09) ‘autonomic blockade’. Chronotropic sensitivity did not differ between healthy and endurance-trained elderly subjects before or after ‘autonomic blockade’. 6. The age-associated reduction in cardiac chronotropic responses to bolus isoprenaline is primarily due to an age-related reduction in the influence of reflex cardiovascular responses on heart rate and not to an age-related reduction in cardiac β-adrenergic sensitivity. Endurance training is not associated with altered β-adrenergic chronotropic sensitivity in the elderly. The transient pressor response to intravenously administered clonidine may be lost in ageing man.

The influence of dynamic visual environments on postural sway in the elderly

1999 ◽  
Vol 9 (3) ◽  
pp. 197-205
Author(s):  
L.L. Borger ◽  
S.L. Whitney ◽  
M.S. Redfern ◽  
J.M. Furman
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Age Groups ◽  
The Elderly ◽  
Visual Scene ◽  
Elderly Subjects ◽  
Mean Velocity ◽  
Healthy Elderly ◽  
Young Subjects

Postural sway during stance has been found to be sensitive to moving visual scenes in young adults, children, and those with vestibular disease. The effect of visual environments on balance in elderly individuals is relatively unknown. The purpose of this study was to compare postural sway responses of healthy elderly to those of young subjects when both groups were exposed to a moving visual scene. Peak to peak, root mean squared, and mean velocity of the center of pressure were analyzed under conditions combining four moving scene amplitudes ( 2 . 5 ∘ , 5 ∘ , 7 . 5 ∘ , 10 ∘ ) and two frequencies of scene movement (0.1 Hz, 0.25 Hz). Each visual condition was tested with a fixed floor and sway referenced platform. Results showed that elderly subjects swayed more than younger subjects when experiencing a moving visual scene under all conditions. The elderly were affected more than the young by sway referencing the platform. The differences between the two age groups were greater at increased amplitudes of scene movement. These results suggest that elderly are more influenced by dynamic visual information for balance than the young, particularly when cues from the ankles are altered.

Effect of sympathetic blockade on diurnal variation of hemodynamic patterns

1989 ◽  
Vol 256 (3) ◽  
pp. R778-R785 ◽  
Author(s):  
M. I. Talan ◽  
B. T. Engel
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Base Line ◽  
Sympathetic Blockade ◽  
Selective Blockade ◽  
Arterial Blood

Heart rate, stroke volume, and intra-arterial blood pressure were monitored continuously in each of four monkeys, 18 consecutive h/day for several weeks. The mean heart rate, stroke volume, cardiac output, systolic and diastolic blood pressure, and total peripheral resistance were calculated for each minute and reduced to hourly means. After base-line data were collected for approximately 20 days, observation was continued for equal periods of time under conditions of alpha-sympathetic blockade, beta-sympathetic blockade, and double sympathetic blockade. This was achieved by intra-arterial infusion of prazosin, atenolol, or a combination of both in concentration sufficient for at least 75% reduction of response to injection of agonists. The results confirmed previous findings of a diurnal pattern characterized by a fall in cardiac output and a rise in total peripheral resistance throughout the night. This pattern was not eliminated by selective blockade, of alpha- or beta-sympathetic receptors or by double sympathetic blockade; in fact, it was exacerbated by sympathetic blockade, indicating that the sympathetic nervous system attenuates these events. Because these findings indicate that blood volume redistribution is probably not the mechanism mediating the observed effects, we have hypothesized that a diurnal loss in plasma volume may mediate the fall in cardiac output and that the rise in total peripheral resistance reflects a homeostatic regulation of arterial pressure.

Carotid baroreceptor control of liver and spleen volume in cats

1991 ◽  
Vol 260 (1) ◽  
pp. H254-H259
Author(s):  
R. Maass-Moreno ◽  
C. F. Rothe
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Total Peripheral Resistance ◽  
Venous Pressure ◽  
Peripheral Resistance ◽  
Normal Brain ◽  
Spleen Volume ◽  
Arterial Blood

We tested the hypothesis that the blood volumes of the spleen and liver of cats are reflexly controlled by the carotid sinus (CS) baroreceptors. In pentobarbital-anesthetized cats the CS area was isolated and perfused so that intracarotid pressure (Pcs) could be controlled while maintaining a normal brain blood perfusion. The volume changes of the liver and spleen were estimated by measuring their thickness using ultrasonic techniques. Cardiac output, systemic arterial blood pressure (Psa), central venous pressure, central blood volume, total peripheral resistance, and heart rate were also measured. In vagotomized cats, increasing Pcs by 100 mmHg caused a significant reduction in Psa (-67.8%), cardiac output (-26.6%), total peripheral resistance (-49.5%), and heart rate (-15%) and significantly increased spleen volume (9.7%, corresponding to a 2.1 +/- 0.5 mm increase in thickness). The liver volume decreased, but only by 1.6% (0.6 +/- 0.2 mm decrease in thickness), a change opposite that observed in the spleen. The changes in cardiovascular variables and in spleen volume suggest that the animals had functioning reflexes. These results indicate that in pentobarbital-anesthetized cats the carotid baroreceptors affect the volume of the spleen but not the liver and suggest that, although the spleen has an active role in the control of arterial blood pressure in the cat, the liver does not.

Oxygen Uptake and Heart Rate Differences between Walking on Land and in Water in the Elderly

1997 ◽  
Vol 5 (2) ◽  
pp. 126-134 ◽  
Author(s):  
Nobuo Takeshima ◽  
Masatoshi Nakata ◽  
Fumio Kobayashi ◽  
Kiyoji Tanaka ◽  
Michael L. Pollock
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Water Immersion ◽  
The Elderly ◽  
Elderly Subjects ◽  
Published Data ◽  
Volume Changes ◽  
Walking Exercise ◽  
Young Subjects ◽  
Walking Speeds

The purpose of this study was to determine the effects of head-out-of-water immersion (HOI) on elderly subjects’ heart rate (HR) and oxygen uptake (V̇O2) responses to graded walking exercise. Subjects were 15 elderly participants. who selected three walking speeds and exercised for 6 min at each intensity on land and in the water. HOI exercise was carried out with subjects immersed to the level of the axilla. HR response at a given V̇O2 during walking with HOI was similar to the values found for walking on land, in contrast to published data on young subjects. The findings are consistent with the hypothesis that water immersion-induced central redistribution of blood volume changes with advancing age and may lead to a difference in the HR–V̇O2 relationship during HOI walking in the elderly compared to the young. This has important implications for prescribing exercise to the elderly when using treadmill HR values for HOI walking training.

Blood Pressure, Heart Rate and Neuroendocrine Responses to a High Carbohydrate and a High Fat Meal in Healthy Young Subjects

1990 ◽  
Vol 79 (5) ◽  
pp. 517-522 ◽  
Author(s):  
D. Heseltine ◽  
J. F. Potter ◽  
G. Hartley ◽  
I. A. MacDonald ◽  
O. F. W. James
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Plasma Insulin ◽  
The Elderly ◽  
High Fat ◽  
High Carbohydrate ◽  
Neuroendocrine Responses ◽  
Young Subjects ◽  
Fat Meal ◽  
Carbohydrate Meal

1. The responses of blood pressure, heart rate, autonomic function and plasma insulin to a high carbohydrate and a high fat meal of equivalent energy value were studied in nine young volunteers. 2. Neither meal produced a significant change in supine or erect blood pressure. The high carbohydrate meal, however, resulted in an overall rise in both supine (6 beats/min) and erect (6 beats/min; P < 0.05) heart rate, no such changes being seen after the high fat meal. 3. Plasma noradrenaline levels increased by a maximum of 126% at 90 min (0.98 to 2.22 nmol/l) after the high carbohydrate meal but were virtually unchanged after the high fat meal (P < 0.01). Parasympathetic function showed no between-meal differences. Plasma insulin and glucose levels were significantly higher after the high carbohydrate meal than after the high fat meal. No postprandial difference in packed cell volume was found between meal types. 4. We conclude that, in young subjects, the postprandial blood pressure after a high carbohydrate meal is maintained by an increase in heart rate associated with increased sympathetic nervous system activity. These changes are at variance with the blood pressure and heart rate responses seen in the elderly after a high carbohydrate meal. A high fat meal has no significant cardiovascular or neuroendocrine effects in the young or old. The nutrient composition of meals has to be taken into account when studying the postprandial cardiovascular and neuroendocrine responses in the young.

Modeling baroreflex regulation of heart rate during orthostatic stress

2006 ◽  
Vol 291 (5) ◽  
pp. R1355-R1368 ◽  
Author(s):  
Mette S. Olufsen ◽  
Hien T. Tran ◽  
Johnny T. Ottesen ◽  
Lewis A. Lipsitz ◽  
Vera Novak
Keyword(s):  
Blood Pressure ◽  
Mathematical Model ◽  
Heart Rate ◽  
Hysteresis Loop ◽  
Elderly People ◽  
Elderly Subjects ◽  
Orthostatic Stress ◽  
Postural Change ◽  
Heart Rate Regulation ◽  
Heart Rate Dynamics

During orthostatic stress, arterial and cardiopulmonary baroreflexes play a key role in maintaining arterial pressure by regulating heart rate. This study presents a mathematical model that can predict the dynamics of heart rate regulation in response to postural change from sitting to standing. The model uses blood pressure measured in the finger as an input to model heart rate dynamics in response to changes in baroreceptor nerve firing rate, sympathetic and parasympathetic responses, vestibulo-sympathetic reflex, and concentrations of norepinephrine and acetylcholine. We formulate an inverse least squares problem for parameter estimation and successfully demonstrate that our mathematical model can accurately predict heart rate dynamics observed in data obtained from healthy young, healthy elderly, and hypertensive elderly subjects. One of our key findings indicates that, to successfully validate our model against clinical data, it is necessary to include the vestibulo-sympathetic reflex. Furthermore, our model reveals that the transfer between the nerve firing and blood pressure is nonlinear and follows a hysteresis curve. In healthy young people, the hysteresis loop is wide, whereas, in healthy and hypertensive elderly people, the hysteresis loop shifts to higher blood pressure values, and its area is diminished. Finally, for hypertensive elderly people, the hysteresis loop is generally not closed, indicating that, during postural change from sitting to standing, baroreflex modulation does not return to steady state during the first minute of standing.

Autonomic Cardiovascular Dysregulation at Rest and During Stress in Chronically Low Blood Pressure

2019 ◽  
Vol 33 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Stefan Duschek ◽  
Alexandra Hoffmann ◽  
Casandra I. Montoro ◽  
Gustavo A. Reyes del Paso
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Baroreflex Sensitivity ◽  
Peripheral Resistance ◽  
Control Group ◽  
Low Blood Pressure

Abstract. Chronic low blood pressure (hypotension) is accompanied by symptoms such as fatigue, reduced drive, faintness, dizziness, cold limbs, and concentration difficulties. The study explored the involvement of aberrances in autonomic cardiovascular control in the origin of this condition. In 40 hypotensive and 40 normotensive subjects, impedance cardiography, electrocardiography, and continuous blood pressure recordings were performed at rest and during stress induced by mental calculation. Parameters of cardiac sympathetic control (i.e., stroke volume, cardiac output, pre-ejection period, total peripheral resistance), parasympathetic control (i.e., heart rate variability), and baroreflex function (i.e., baroreflex sensitivity) were obtained. The hypotensive group exhibited markedly lower stroke volume, heart rate, and cardiac output, as well as higher pre-ejection period and baroreflex sensitivity than the control group. Hypotension was furthermore associated with a smaller blood pressure response during stress. No group differences arose in total peripheral resistance and heart rate variability. While reduced beta-adrenergic myocardial drive seems to constitute the principal feature of the autonomic impairment that characterizes chronic hypotension, baroreflex-related mechanisms may also contribute to this state. Insufficient organ perfusion due to reduced cardiac output and deficient cardiovascular adjustment to situational requirements may be involved in the manifestation of bodily and mental symptoms.

PERIPHERAL HEMODYNAMICS PECULIARITIES IN YOUNG AND MIDDLE-AGED MEN WITH A RECIDIVATING MYOCARDIAL INFARCTION

2021 ◽  
pp. 51-57
Author(s):  
Golikov A.V. ◽  
Epifanov S.Yu. ◽  
Reiza V.A.
Keyword(s):  
Myocardial Infarction ◽  
Blood Pressure ◽  
Heart Rate ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Study Group ◽  
Poor Outcome ◽  
Peripheral Hemodynamics ◽  
Recurrent Myocardial Infarction ◽  
Recurrent Ischemia

Relevance. Hemodynamics changes in recidivating myocardial infarction and early postinfarction angina are not well understood. In recent years, the frequency of these complications has been increasing. Aim. To evaluate peripheral hemodynamics changes in men under 60 years old with recurrent myocardial infarction and early postinfarction angina to improve prevention and outcomes. Material and methods. The study included men aged 19-60 years old with type I myocardial infarction. Patients are divided into two age-comparable groups: I - the study group, with recurrent myocardial infarction - 102 patients; II - control, without it - 541 patients. A comparative assessment of hemodynamics changes in first 48 hours (1) and the end of third week disease (2), also risk analysis of recurrent ischemia and poor outcome in selected groups were performed. Results. The study group was distinguished by a high level of total peripheral resistance1 (2055.5±965.2 (dyn×sec×cm-5)) from the control (2055.5± 965.2 (dyn×sec×cm-5); p=0.02). In both groups, a decrease in the values of all indicators was noted (p<0.05). A more pronounced decrease in total peripheral resistance was found in the study group, and in the parameters of blood pressure and heart rate - in the control group. The values of total peripheral resistance1 ≥1600 dyne×sec×cm-5 were the markers of the risk of ischemia recurrence. Predictors of poor outcome are blood pressure levels1 (systolic <97; diastolic <70; mean <93.3 (mm Hg)); total peripheral resistance1 <1746.2 dyne×sec×cm-5 and heart rate (˃92 per min). Conclusions. Patients with recurrent ischemia are characterized by higher levels of total peripheral resistance in the first hours of myocardial infarction. For both groups, a decrease in all studied indicators is determined. The above values of hemodynamic parameters should be used in the formation of groups with a high risk of early recurrence of ischemia and an unfavorable outcome, as well as for prognostic modeling of these complications.

MO096ROLE OF THE ENDOTHELIN SYSTEM IN THE INTERACTIONS OF THE VASOPRESSOR SYSTEMS IN VIVO IN MEN - IMPORTANCE OF GENETIC HOST FACTORS

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Bastian Brune ◽  
Johannes Korth ◽  
Sebastian Dolff ◽  
Benjamin Wilde ◽  
Winfried Siffert ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Hypertension ◽  
Dose Response ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Oral Application ◽  
Endothelin System ◽  
C825t Polymorphism ◽  
Gnb3 C825t

Abstract Background and Aims Arterial hypertension is one of the most common diseases of the cardiovascular system worldwide and is still the cause of most deaths in Germany. Data on interactions of the endothelin-system with the renin-angiotensin- and the sympathoadrenergic system in the regulation of systemic hemodynamics in humans are lacking. In our present investigation we study the effects of Endothelin A-, Alpha1- and Angiotensin II-type-1-receptor antagonization on the systemic pressor effects of intravenous Endothelin-1-application in young, healthy men. In addition, we analyzed the effects of the genetic variations of the GNB3 C825T-polymorphism on hemodynamic changes. GNB3 825CT/TT-allele-carriers are considered to have a higher risk for multiple diseases with structural, vascular degeneration, such as arterial hypertension, diabetes mellitus and obesity. Method 21 healthy male volunteers were included in this double- blind, randomized, placebo-controlled cross-over study and were studied on four days. Endothelin-1 (ET-1) (0.5, 1, 2.5, 5 ng/kg/min for 20 min each) was given intravenous 2.0 hours after oral application of either placebo or Doxazosin, 3.5 hours after oral application of Candesartan (Candesartan 8 mg) or in the presence of a continuous infusion of the ET-A-selective antagonist BQ123 (60 μg/min). Blood pressure (BP) and heart rate (HR) were recorded and total peripheral resistance (TPR) was measured using impedance cardiography. ET-1-dose-response curves were analyzed with ANOVA. Data are presented as mean ± SD. Since we suspected an effect of the GNB3 C825T-polymorphism we divided the overall collective into 2 sub-collectives according to the GNB3 C825T-genotypes (n = 21, GNB3 825CC: n = 10, GNB3 825CT/TT: n = 11). Our analyses considered the overall collective and compared the sub-collectives intraday and interday. Results ET-1 increased systolic blood pressure (SBD) (p ≤ 0,01), diastolic blood pressure (DBD) and mean arterial pressure (MBP) as well as total peripheral resistance (TPR) (each p ≤ 0,001) with decreasing heart rate (HR5) (p ≤ 0,05). Elevation of blood pressure existed in both sub-collectives (GNB3 825CC: SBD & MBD: p ≤ 0,01, DBP & TPR: p ≤ 0,05, GNB3 825CT/TT: DBD, MBD & TPR: p ≤ 0,01, SBP p ≤ 0,05). Antagonization of ETA-receptors reversed the effect in the overall collective as well as in the sub-collectives. Both, Doxazosin, as well as Candesartan led to a decrease in blood pressure, however, dose-response relationship was influenced more by doxazosin (DBD: p ≤ 0,001, MBD: p ≤ 0,01) than by candesartan (all values: p &gt; 0,05). For both drugs, blood pressure and TPR remained elevated under maximum ET-1-application compared to baseline measurement. Blood pressure dependent heart rate changes were observed in the overall collective and in GNB3 825CC-allele-carriers under sole ET-1-therapy (p ≤ 0.05) (Fig. 1). Candesartan reversed the effect of ET-1 on the sub-collectives (p &gt; 0.05). GNB3 825CT/TT-allele-carriers showed no reduction in heart rate under ET-1-application, but with accompanying candesartan therapy (p ≤ 0.01) (Fig. 2). The genotype collectives thus behaved oppositely to the drugs in this respect. Conclusion In summary, ET-1 increased systolic, diastolic and mean arterial blood pressure as well as systemic vascular resistance. Doxazosin, Candesartan and BQ123 led to a decrease in blood pressure. Blood pressure and TPR remained elevated under maximum ET-1 application plus Candesartan or Doxazosin. The heart rate changes of the genotype-separated sub-collectives were opposite when ET-1 was administered compared to ET-1 and Candesartan.

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