Cardiovascular Changes in the Lingcod (Ophiodon Elongatus) Following Adrenergic and Cholinergic Drug Infusions

Heart rate, stroke volume, and intra-arterial blood pressures were monitored continuously in each of four monkeys for 18 consecutive hours, 5 days/wk, for several weeks. Mean heart rate, stroke volume, cardiac output, systolic and diastolic pressure, and total peripheral resistance were calculated each minute, and these averages were analyzed further to yield hourly means and intercorrelations. The main findings from the analyses of mean levels were that cardiac output fell throughout the night and that peripheral resistance rose during the same interval so that arterial pressure fell only slightly; the highest levels of peripheral resistance and lowest levels of cardiac output were recorded between 0500 and 0700. Furthermore, the levels of these responses during the remainder of the morning were higher (peripheral resistance) and lower (cardiac output) than those recorded in the evening.

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Cardiovascular changes in the unanaesthetized lingcod (Ophiodon elongatus) during short-term, progressive hypoxia and spontaneous activity

Canadian Journal of Zoology ◽

10.1139/z82-127 ◽

1982 ◽

Vol 60 (5) ◽

pp. 933-941 ◽

Cited By ~ 39

Author(s):

A. P. Farrell

Keyword(s):

Cardiac Output ◽

Spontaneous Activity ◽

Active Component ◽

Short Term ◽

Vascular Conductance ◽

Ophiodon Elongatus ◽

Arterial Blood ◽

Blood Pressures ◽

Progressive Hypoxia ◽

Conductance Changes

Cardiac output [Formula: see text] and arterial blood pressures in the ventral and dorsal aortae (PVAnd PDA) were measured directly and simultaneously in the lingcod. The branchial and systemic conductances to blood flow (Gg and Gs) were calculated. During progressive hypoxia [Formula: see text], Gg, Gs, PVA, and PDA were all reduced when the water [Formula: see text] decreased below 45 mmHg (1 mmHg = 133.322 Pa). Spontaneous activity was characterized by an initial bradycardia and concurrent reduction in [Formula: see text], Gg, Gs, PVA, and PDA. Longer periods of activity were subsequently followed by a period of restitution where [Formula: see text], Gg, Gs, PVA, and PDA were all elevated.The beat by beat oscillations in flow were usually synchronized with, and in the same direction as, those in vascular conductance during both activity and hypoxia. This synchrony was most apparent between Gs and [Formula: see text] during the rapid cardiovascular adjustments occurring with activity. It is suggested that the observed relationship between flow and conductance changes was a result of passive changes in conductance when flow was altered, plus an active component which involved reflex vasoactivity.

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Cardiac function and circulation in hagfishes

Canadian Journal of Zoology ◽

10.1139/z91-277 ◽

1991 ◽

Vol 69 (7) ◽

pp. 1985-1992 ◽

Cited By ~ 27

Author(s):

Malcolm E. Forster ◽

Michael Axelsson ◽

Anthony P. Farrell ◽

Stefan Nilsson

Keyword(s):

Cardiac Output ◽

Cardiac Function ◽

Energy Requirement ◽

High Volume ◽

Aortic Pressure ◽

Arterial Blood ◽

Branchial Heart ◽

Blood Pressures

The hagfish circulation contains a high volume of blood (180 mL∙kg−1) and is remarkable for the number of accessory pumps. Cardiac output from the branchial heart of hagfishes is comparable to that of elasmobranch and most teleost fishes, but blood pressures are considerably lower than in any other vertebrate group. Cardiac output is extremely sensitive to both venous return and ventral aortic pressure (afterload). Owing to the low arterial blood pressures, myocardial power output is lower than for any other vertebrate heart. The concomitant low energy requirement of the myocardium allows ATP generated anaerobically through glycolysis to maintain cardiac output during severe hypoxia. In vivo and in vitro administration of adrenergic agonists and antagonists increase and decrease cardiac performance, respectively. This suggests that the catecholamines that are stored beneath the endothelium of the branchial and portal hearts are involved in the tonic control of cardiac function.

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Cardiac output by pulse contour analysis does not match the increase measured by rebreathing during human spaceflight

Journal of Applied Physiology ◽

10.1152/japplphysiol.00651.2017 ◽

2017 ◽

Vol 123 (5) ◽

pp. 1145-1149 ◽

Cited By ~ 6

Author(s):

Richard L. Hughson ◽

Sean D. Peterson ◽

Nicholas J. Yee ◽

Danielle K. Greaves

Keyword(s):

Cardiac Output ◽

Stroke Volume ◽

Cardiac Function ◽

Pulse Contour Analysis ◽

Pulse Contour ◽

Alternative Methods ◽

Contour Analysis ◽

Windkessel Model ◽

Human Spaceflight ◽

Arterial Blood

Pulse contour analysis of the noninvasive finger arterial pressure waveform provides a convenient means to estimate cardiac output (Q̇). The method has been compared with standard methods under a range of conditions but never before during spaceflight. We compared pulse contour analysis with the Modelflow algorithm to estimates of Q̇ obtained by rebreathing during preflight baseline testing and during the final month of long-duration spaceflight in nine healthy male astronauts. By Modelflow analysis, stroke volume was greater in supine baseline than seated baseline or inflight. Heart rate was reduced in supine baseline so that there were no differences in Q̇ by Modelflow estimate between the supine (7.02 ± 1.31 l/min, means ± SD), seated (6.60 ± 1.95 l/min), or inflight (5.91 ± 1.15 l/min) conditions. In contrast, rebreathing estimates of Q̇ increased from seated baseline (4.76 ± 0.67 l/min) to inflight (7.00 ± 1.39 l/min, significant interaction effect of method and spaceflight, P < 0.001). Pulse contour analysis utilizes a three-element Windkessel model that incorporates parameters dependent on aortic pressure-area relationships that are assumed to represent the entire circulation. We propose that a large increase in vascular compliance in the splanchnic circulation invalidates the model under conditions of spaceflight. Future spaceflight research measuring cardiac function needs to consider this important limitation for assessing absolute values of Q̇ and stroke volume. NEW & NOTEWORTHY Noninvasive assessment of cardiac function during human spaceflight is an important tool to monitor astronaut health. This study demonstrated that pulse contour analysis of finger arterial blood pressure to estimate cardiac output failed to track the 46% increase measured by a rebreathing method. These results strongly suggest that alternative methods not dependent on pulse contour analysis are required to track cardiac function in spaceflight.

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Breathing through an inspiratory threshold device improves stroke volume during central hypovolemia in humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.00439.2007 ◽

2008 ◽

Vol 104 (5) ◽

pp. 1402-1409 ◽

Cited By ~ 46

Author(s):

Kathy L. Ryan ◽

William H. Cooke ◽

Caroline A. Rickards ◽

Keith G. Lurie ◽

Victor A. Convertino

Keyword(s):

Cardiac Output ◽

Arterial Pressure ◽

Stroke Volume ◽

Lower Body Negative Pressure ◽

Systolic Arterial Pressure ◽

Intrathoracic Pressure ◽

Subsequent Increase ◽

Arterial Blood ◽

Threshold Device ◽

Inspiratory Resistance

Inspiratory resistance induced by breathing through an impedance threshold device (ITD) reduces intrathoracic pressure and increases stroke volume (SV) in supine normovolemic humans. We hypothesized that breathing through an ITD would also be associated with a protection of SV and a subsequent increase in the tolerance to progressive central hypovolemia. Eight volunteers (5 men, 3 women) were instrumented to record ECG and beat-by-beat arterial pressure and SV (Finometer). Tolerance to progressive lower body negative pressure (LBNP) was assessed while subjects breathed against either 0 (sham ITD) or −7 cmH2O inspiratory resistance (active ITD); experiments were performed on separate days. Because the active ITD increased LBNP tolerance time from 2,014 ± 106 to 2,259 ± 138 s ( P = 0.006), data were analyzed (time and frequency domains) under both conditions at the time at which cardiovascular collapse occurred during the sham experiment to determine the mechanisms underlying this protective effect. At this time point, arterial blood pressure, SV, and cardiac output were higher ( P ≤ 0.005) when breathing on the active ITD rather than the sham ITD, whereas indirect indicators of autonomic activity (low- and high-frequency oscillations of the R-to-R interval) were not altered. ITD breathing did not alter the transfer function between systolic arterial pressure and R-to-R interval, indicating that integrated baroreflex sensitivity was similar between the two conditions. These data show that breathing against inspiratory resistance increases tolerance to progressive central hypovolemia by better maintaining SV, cardiac output, and arterial blood pressures via primarily mechanical rather than neural mechanisms.

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Non-Invasive Scale Measurement of Cardiac Output Compared with the Gold-Standard Direct Fick Method: A Feasibility Study

10.1101/2021.03.28.21254243 ◽

2021 ◽

Author(s):

Daniel Yazdi ◽

Sarin Patel ◽

Suriya Sridaran ◽

Evan Wilson ◽

Sarah Smith ◽

...

Keyword(s):

Cardiac Output ◽

Stroke Volume ◽

Cardiac Function ◽

Exercise Test ◽

Gold Standard ◽

Cardiopulmonary Exercise Test ◽

Cardiac Monitoring ◽

Non Invasive ◽

Cardiopulmonary Exercise ◽

The Mean

AbstractBackgroundObjective markers of cardiac function are limited in the outpatient setting and may be beneficial for monitoring patients with chronic cardiac conditions.ObjectiveWe assess the accuracy of a scale, with the ability to capture ballistocardiography, electrocardiography, and impedance plethysmography signals from a patient’s feet while standing on the scale, in measuring stroke volume and cardiac output compared to the gold-standard direct Fick method.MethodsThirty-two patients with unexplained dyspnea undergoing level 3 invasive cardiopulmonary exercise test at a tertiary medical center were included in the final analysis. We obtained scale and direct Fick measurements of stroke volume and cardiac output before and immediately after invasive cardiopulmonary exercise test.ResultsStroke volume and cardiac output from a cardiac scale and the direct Fick method correlated with r = 0.81 and r = 0.85, respectively (P < 0.001 each). The mean absolute error of the scale estimated stroke volume was -1.58 mL, with a 95% limits of agreement (LOA) of -21.97 mL to 18.81 mL. The mean error for the scale estimated cardiac output was -0.31 L/min, with a 95% LOA of -2.62 L/min to 2.00 L/min. The change in stroke volume and cardiac output before and after exercise were 78.9% and 96.7% concordant, respectively between the two measuring methods.ConclusionsThis novel scale with cardiac monitoring abilities may allow for non-invasive, longitudinal measures of cardiac function. Using the widely accepted form factor of a bathroom scale, this method of monitoring can be easily integrated into a patient’s lifestyle.

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Effect of sympathetic blockade on diurnal variation of hemodynamic patterns

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.256.3.r778 ◽

1989 ◽

Vol 256 (3) ◽

pp. R778-R785 ◽

Cited By ~ 4

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.

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Systemic hemodynamic determinants of blood pressure in women: age, physical activity, and hormone replacement

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.273.2.h777 ◽

1997 ◽

Vol 273 (2) ◽

pp. H777-H785 ◽

Cited By ~ 2

Author(s):

B. E. Hunt ◽

K. P. Davy ◽

P. P. Jones ◽

C. A. DeSouza ◽

R. E. Van Pelt ◽

...

Keyword(s):

Physical Activity ◽

Blood Pressure ◽

Cardiac Output ◽

Oxygen Consumption ◽

Stroke Volume ◽

Hormone Replacement ◽

Systemic Hemodynamic ◽

Arterial Blood ◽

Age Related ◽

Hemodynamic Determinants

We tested the hypothesis that the age-related changes in systemic hemodynamic determinants of arterial blood pressure in healthy women are related to physical activity and hormone replacement status. We studied 66 healthy, normotensive premenopausal (21-35 yr) and postmenopausal (50-72 yr) sedentary and endurance-trained women under supine resting conditions. Mean blood pressure was 7 mmHg higher in sedentary post- compared with premenopausal women, which was associated with an 11-mmHg higher systolic blood pressure, a 25% lower stroke volume and cardiac output, and a 50% higher systemic vascular resistance (all P < 0.05). Absolute (ml) levels of total blood volume did not differ across age, but resting oxygen consumption was approximately 35% lower in the postmenopausal women (P < 0.05). The elevations in mean and systolic blood pressures with age were similar in endurance-trained runners, but, in contrast to the sedentary women, the elevations were not associated with significant age-related differences in cardiac output, stroke volume, or oxygen consumption, and only a modest (15%) increase in systemic vascular resistance (P = 0.06). Postmenopausal swimmers demonstrated the same systemic hemodynamic profile as that of postmenopausal runners, indicating a nonspecific influence of the endurance-trained state. Blood pressure and its systemic hemodynamic determinants did not differ in postmenopausal users compared with those of nonusers of hormone replacement therapy. Resting oxygen consumption was the strongest physiological correlate of cardiac output in the overall population (r = 0.65, P < 0.001). We conclude that 1) the increases in arterial blood pressure at rest with age in healthy normotensive women are not obviously related to habitual physical activity status; 2) the systemic hemodynamic determinants of the age-related elevations in blood pressure are fundamentally different in sedentary vs. active women, possibly due, in part, to an absence of decline in resting oxygen consumption in the latter; and 3) systemic hemodynamics at rest are not different in healthy normotensive postmenopausal users vs. nonusers of estrogen-based hormone replacement.

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Increase of heart rate without elevation of cardiac output in adult Atlantic salmon (Salmo salar) exposed to acidic water and aluminium

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-168 ◽

1999 ◽

Vol 56 (2) ◽

pp. 184-190 ◽

Cited By ~ 7

Author(s):

Julie C Brodeur ◽

Trine Ytrestøyl ◽

Bengt Finstad ◽

R Scott McKinley

Keyword(s):

Heart Rate ◽

Cardiac Output ◽

Atlantic Salmon ◽

Stroke Volume ◽

River Water ◽

Salmo Salar ◽

Exposure Period ◽

Atlantic Salmon Salmo Salar ◽

Concomitant Reduction ◽

Ventral Aorta

Adult Atlantic salmon (Salmo salar) were exposed for 48 h to water from acidified (pH 5.2) Fossbekk River (Norway), with and without 94 µg aluminium (Al)/L added as AlCl3, and to water from circumneutral (pH 6.7) Ims River (Norway) (controls). Cardiac output, heart rate, and stroke volume were monitored throughout the exposure period with Doppler flow probes placed around the ventral aorta of the fish. Fish exposed to Fossbekk River water without added Al showed few physiological disturbances. When 94 µg Al/L was added to Fossbekk River water, most of the fish died before the end of the 48-h exposure period, and a large elevation in heart rate was observed together with a decrease in plasma chloride concentrations and an increase in haematocrit, plasma glucose and plasma cortisol levels. Cardiac output was maintained at basal levels during the first 24 h of exposure because the tachycardia was accompanied by a concomitant reduction of stroke volume. Signs of arrhythmia appeared after 32 h of exposure and were associated with a further decrease in stroke volume that caused cardiac output to decrease below basal levels. The incapacity of the tachycardia to elevate cardiac output and the subsequent death of the fish suggest that this response to low pH and Al is more of a maladaptation reaction than a compensatory or adaptative reaction.

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Differential effects of endothelin-1 on isolated working rat hearts before and after ischaemia and reperfusion

Clinical Science ◽

10.1042/cs103s189s ◽

2002 ◽

Vol 103 (s2002) ◽

pp. 189S-193S ◽

Cited By ~ 2

Author(s):

Andrew T. GOODWIN ◽

Mohamed AMRANI ◽

Caroline C. GRAY ◽

Jay JAYAKUMAR ◽

Adrian J. MARCHBANK ◽

...

Keyword(s):

Cardiac Output ◽

Stroke Volume ◽

Cardiac Function ◽

Physiological Role ◽

Rate Of Change ◽

Cardioplegic Arrest ◽

Beneficial Effects ◽

Rat Hearts ◽

Before And After ◽

Dose Dependent Decrease

Endothelin (ET) may have both detrimental (reduced coronary flow) and beneficial effects (positive inotrope, reduced arrhythmogenesis) following ischaemia. We examined the effects of ET on cardiac function during reperfusion following prolonged hypothermic cardioplegic arrest in a protocol mimicking cardiac transplantation. Isolated working rat hearts were perfused with Krebs buffer to which increasing concentrations of ET-1 or sarafotoxin S6c had been added. Identical experiments were performed after 4h of cardioplegic arrest at 4°C. Under pre-ischaemic conditions ET-1 caused a dose-dependent decrease in cardiac function compared with controls. In contrast, following ischaemia low doses of ET-1 (10-10 M) caused a significant and beneficial increase in cardiac output (109.1% versus 81.3%), dP/dt i.e. the rate of change of pressure with time (94.7% versus 75.6%) and stroke volume (100.3% versus 77.5%) compared with controls (P<0.05). At higher doses of ET-1 there was a detrimental effect on cardiac output, dP/dt and stroke volume similar to that seen prior to ischaemia. Sarafotoxin S6c had no significant effect pre or post ischaemia on any of the parameters measured compared with controls (P = not significant). ET-1 at low concentrations during reperfusion can improve the recovery of cardiac function mediated via ETA receptors. ET may play an important physiological role in the recovery of cardiac function following prolonged ischaemia.

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