Effect of exercise on cardiac output and distribution of uterine blood flow in pregnant ewes

1976 ◽  
Vol 40 (5) ◽  
pp. 725-728 ◽  
Author(s):  
L. B. Curet ◽  
J. A. Orr ◽  
H. G. Rankin ◽  
T. Ungerer
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Stroke Volume ◽  
Physical Training ◽  
Exercise Stress ◽  
Compensatory Mechanism ◽  
Uterine Blood Flow ◽  
Flow Measurements ◽  
Before And After ◽  
Blood Flow Measurements

This study was designed to determine what effect physical training has on heart rate and stroke volume responses to exercise stress and to determine if exercise altered the distribution of uterine blood flow. Measurements were made in ten pregnant ewes at rest and immediately following exercise on a treadmill. Five ewes underwent physical training for 3 wk prior to measurement. An increase in heart rate with no change in stroke volume was observed following exercise in both trained and untrained ewes. Total uterine blood flow was not changed following exercise, but distribution was altered in favor of the placenta. Blood flow was evenly distributed within the placenta before and after exercise. The redistribution of flow to the placenta that occurs after exercise. tphe redistribution of flow to the placenta that occurs after exercise might represent a compensatory mechanism for the fetus.

Heart rate and stroke volume contribution to cardiac output in swimming yellowfin tuna: response to exercise and temperature.

1997 ◽  
Vol 200 (14) ◽  
pp. 1975-1986 ◽  
Author(s):  
K E Korsmeyer ◽  
N C Lai ◽  
R E Shadwick ◽  
J B Graham
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Fork Length ◽  
Yellowfin Tuna ◽  
Swimming Velocity ◽  
Flow Measurements ◽  
C 30 ◽  
Blood Flow Measurements

Cardiac performance in the yellowfin tuna (Thunnus albacares, 673-2470 g, 33-53 cm fork length, FL) was examined in unanesthetized fish swimming in a large water tunnel. Yellowfin tuna were fitted with either electrocardiogram electrodes or a transcutaneous Doppler blood-flow probe over the ventral aorta and exposed to changes in swimming velocity (range 0.8-2.9 FLs-1) or to an acute change in temperature (18-28 degrees C). Heart rates (fH) at +/-1 degree C (30-130 beats min-1) were lower on average than previous measurements with non-swimming (restrained) tunas and comparable with those for other active teleosts at similar relative swimming velocities. Although highly variable among individuals, fH increased with velocity (U, in FLs-1) in all fish (fH = 17.93U + 49.93, r2 = 0.14, P < 0.0001). Heart rate was rapidly and strongly affected by temperature (Q10 = 2.37). Blood flow measurements revealed a mean increase in relative cardiac output of 13.6 +/- 3.0% with exercise (mean velocities 1.23-2.10 FLs-1) caused by an 18.8 +/- 5.4% increase in fH and a 3.9 +/- 2.3% decrease in stroke volume. These results indicate that, unlike most other fishes, cardiac output in yellowfin tuna is regulated primarily through increases in fH. Acute reductions in ambient temperature at slow swimming velocities resulted in decreases in cardiac output (Q10 = 1.52) and fH (Q10 = 2.16), but increases in stroke volume (Q10 = 0.78). This observation suggests that the lack of an increase in stroke volume during exercise is not due to the tuna heart operating at maximal anatomical limits.

scholarly journals Improved brain perfusion after electrical cardioversion of atrial fibrillation

EP Europace ◽  
2019 ◽  
Vol 22 (4) ◽  
pp. 530-537 ◽  
Author(s):  
Marianna Gardarsdottir ◽  
Sigurdur Sigurdsson ◽  
Thor Aspelund ◽  
Valdis Anna Gardarsdottir ◽  
Lars Forsberg ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Atrial Fibrillation ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Brain Perfusion ◽  
Resonance Imaging ◽  
Flow Measurements ◽  
Before And After ◽  
Blood Flow Measurements

Abstract Aims Atrial fibrillation (AF) has been associated with reduced brain volume, cognitive impairment, and reduced cerebral blood flow. The causes of reduced cerebral blood flow in AF are unknown, but no reduction was seen in individuals without the arrhythmia in a previous study. The aim of this study was to test the hypothesis that brain perfusion, measured with magnetic resonance imaging (MRI), improves after cardioversion of AF to sinus rhythm (SR). Methods and results All patients undergoing elective cardioversion at our institution were invited to participate. A total of 44 individuals were included. Magnetic resonance imaging studies were done before and after cardioversion with both brain perfusion and cerebral blood flow measurements. However, 17 did not complete the second MRI as they had a recurrence of AF during the observation period (recurrent AF group), leaving 17 in the SR group and 10 in the AF group to complete both measurements. Brain perfusion increased after cardioversion to SR by 4.9 mL/100 g/min in the whole brain (P < 0.001) and by 5.6 mL/100 g/min in grey matter (P < 0.001). Cerebral blood flow increased by 58.6 mL/min (P < 0.05). Both brain perfusion and cerebral blood flow remained unchanged when cardioversion was unsuccessful. Conclusion In this study of individuals undergoing elective cardioversion for AF, restoration, and maintenance of SR for at least 10 weeks after was associated with an improvement of brain perfusion and cerebral blood flow measured by both arterial spin labelling and phase contrast MRI. In those individuals where cardioversion was unsuccessful, there was no change in perfusion or blood flow.

REPRODUCIBILITY OF INTESTINAL BLOOD FLOW MEASUREMENTS BEFORE AND AFTER 1 HOUR CYCLING

1995 ◽  
Vol 27 (Supplement) ◽  
pp. S65
Author(s):  
Peters HPF ◽  
D de Leeuw ◽  
R C Lapham ◽  
E Bol ◽  
M S van Leeuwen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intestinal Blood Flow ◽  
Flow Measurements ◽  
Before And After ◽  
Blood Flow Measurements

Systemic and uterine responses to chronic infusion of estradiol-17 beta

1993 ◽  
Vol 265 (5) ◽  
pp. E690-E698 ◽  
Author(s):  
R. R. Magness ◽  
C. R. Parker ◽  
C. R. Rosenfeld
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Angiotensin Ii ◽  
Mean Arterial Pressure ◽  
Stroke Volume ◽  
Ang Ii ◽  
Uterine Blood Flow ◽  
Pressor Responses ◽  
Chronic Infusion

Human and ovine pregnancies are associated with increases in plasma levels of estrogens and angiotensin II (ANG II), cardiac output (CO), blood volume (BV), and uterine blood flow (UBF), as well as attenuated ANG II pressor responses. We hypothesized that, in nonpregnant animals, prolonged estradiol-17 beta (E2 beta) treatment would reproduce these endocrine and hemodynamic alterations. Nonpregnant ovariectomized ewes (n = 5) received 5 microgram E2 beta/kg iv followed by 220 micrograms/day for 14 days. Plasma E2 beta increased from 36 +/- 6 to 269 +/- 79 (SE) pg/ml (P < 0.05) during E2 beta treatment, returning to control values 4 days posttreatment. By 3 days of E2 beta, mean arterial pressure (MAP) and systemic vascular resistance (SVR) fell 9 +/- 1 and 29 +/- 1%, whereas heart rate (HR) and CO increased 20 +/- 5 and 26 +/- 1% (P < 0.05). Stroke volume (SV), BV, and plasma volume were unchanged until 7 days of E2 beta, with values rising 17 +/- 5, 13 +/- 3, and 14 +/- 4, respectively (P < 0.05). Although MAP remained similarly depressed (-11 +/- 1%) during week 2 of E2 beta, SVR decreased further (-37 +/- 3%) and was associated with additional increases (P < 0.05) in CO to 44 +/- 5%, reflecting rises in SV (21 +/- 2%) but not HR. Increases in BV correlated with rises in CO (r = 0.55) and SV (r = 0.64) but not HR (r = -0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular Changes in Preterm Infants Nursed Under Radiant Warmers

PEDIATRICS ◽  
1987 ◽  
Vol 80 (2) ◽  
pp. 235-239
Author(s):  
Frans J. Walther ◽  
Paul Y.K. Wu ◽  
Bijan Siassi
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Newborn Infants ◽  
Cardiovascular Effects ◽  
Radiant Heat ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Radiant Warmer

Radiant heat is known to increase insensible water loss and, to a certain extent, oxygen consumption. Little is known about its cardiovascular effects. We measured cardiac output, stroke volume, heart rate, and lower limb and skin blood flow in 20 preterm newborn infants nursed in an incubator and under a radiant warmer at an abdominal skin temperature of 36.5°C. Mean (±SEM) birth weight was 1.57 (0.06) kg, gestational age 31.7 (0.4) weeks, and weight at examination 1.69 (0.02) kg; median postnatal age was 15 days. Skin and limb blood flow measurements increased by 44% to 55% with radiant heat (P &lt; .001 and P &lt; .01, respectively). Cardiac output increased by 5.4% (P &lt; .02) under the radiant warmer secondary to a small but significant (P &lt; .05) increase in heart rate. The changes in cardiac output during radiant heat administration are comparable to those reported for oxygen consumption.

scholarly journals Effects of Venesection on Cerebral Function in Chronic Lung Disease

1980 ◽  
Vol 7 (4) ◽  
pp. 293-296 ◽  
Author(s):  
R. Bornstein ◽  
D. Menon ◽  
E. York ◽  
B. Sproule ◽  
C. Zak
Keyword(s):  
Blood Flow ◽  
Neuropsychological Testing ◽  
Chronic Obstructive ◽  
Mental Function ◽  
Cerebral Function ◽  
Regional Cerebral Blood ◽  
Flow Measurements ◽  
Obstructive Pulmonary Disease ◽  
Before And After ◽  
Blood Flow Measurements

SUMMARY:Regional cerebral blood flow measurements and neuropsychological testing were conducted before and after venesection on 6 patients with polycythemia secondary to chronic obstructive pulmonary disease. Venesection resulted in lowered viscosity and hematocrit, and an accompanying improvement in cerebral perfusion and mental function. Blood flow was significantly increased in the left cerebral hemisphere following phlebotomy, and there was significant improvement in sensory I mental function. Cerebral function would appear to be related to blood flow alterations influenced by the viscosity of the blood.

Hemodynamic effects of a combination of clonidine and propranolol in conscious cirrhotic rats

1989 ◽  
Vol 67 (10) ◽  
pp. 1369-1372 ◽  
Author(s):  
Dominique Roulot ◽  
Christophe Gaudin ◽  
Alain Braillon ◽  
Tatsuya Sekiyama ◽  
Yannick Bacq ◽  
...  
Keyword(s):  
Blood Flow ◽  
Portal Hypertension ◽  
Portal Pressure ◽  
Biliary Cirrhosis ◽  
Hemodynamic Effects ◽  
Hemodynamic Changes ◽  
Flow Measurements ◽  
Before And After ◽  
Radioactive Microsphere Method ◽  
Blood Flow Measurements

The hemodynamic effects of the combination of clonidine and propranolol were studied in conscious rats with portal hypertension owing to secondary biliary cirrhosis. Pressure and blood flow measurements (radioactive microsphere method) were performed in three groups of eight rats before and after drug administration. The combined effects of clonidine (2 μg/100 g body wt., i.v.) and propranolol (0.2 mg/min for 10 min) were compared with those observed after administration of either clonidine alone or propranolol alone. The association of clonidine and propranolol induced significant decreases in portal pressure (30%) and portal tributary blood flow (43%), the magnitude of these changes being significantly more marked than that after administration of either clonidine alone (12 and 20%, respectively) or propranolol alone (16 and 17%, respectively). After the combination, no significant change in arterial pressure was observed, but cardiac output significantly decreased and systemic vascular resistance significantly increased. Renal blood flow decreased to a similar extent (40%) in the three groups. These findings indicate that the combination of clonidine and propranolol is more effective for reversing splanchnic hemodynamic changes than clonidine alone or propranolol alone. The additive effects of this association are in agreement with the action of clonidine and propranolol at different levels (central and peripheral) and on different receptors (α and β). It suggests that an increase in sympathetic activity may play a major role in hemodynamic changes observed in experimental cirrhosis.Key words: portal hypertension, cirrhosis, splanchnic blood flow, α2-adrenergic agonist, β-blocker.

scholarly journals Passive hallux adduction decreases lateral plantar artery blood flow: a preliminary study of the potential influence of narrow toe box shoes

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Julia L. Jacobs ◽  
Sarah T. Ridge ◽  
Dustin A. Bruening ◽  
K. Annie Brewerton ◽  
Jayson R. Gifford ◽  
...  
Keyword(s):  
Blood Flow ◽  
Artery Blood Flow ◽  
Arch Height ◽  
Abductor Hallucis ◽  
Flow Measurements ◽  
Medial Side ◽  
Negative Change ◽  
Plantar Artery ◽  
Before And After ◽  
Blood Flow Measurements

Abstract Background Blood flow is essential in maintaining tissue health. Thus, compromised blood flow can prevent tissue healing. An adducted hallux, as seen inside a narrow shoe, may put passive tension on the abductor hallucis, compressing the lateral plantar artery into the calcaneus and restricting blood flow. The purposes of this study were to compare lateral plantar artery blood flow before and after passive hallux adduction and to compare blood flow with arch height. Methods Forty-five healthy volunteers (20 female, 25 male; age = 24.8 ± 6.8 yr; height = 1.7 ± 0.1 m; weight = 73.4 ± 13.5 kg) participated in this cross-over design study. Arch height index (AHI) was calculated, and blood flow measurements were obtained using ultrasound (L8-18i transducer, GE Logiq S8). The lateral plantar artery was imaged deep to abductor hallucis for 120 s: 60 s at rest, then 60 s of passive hallux adduction. Maximal passive hallux adduction was performed by applying pressure to the medial side of the hallux. Blood flow was calculated in mL/min, and pre-passive hallux adduction was compared to blood flow during passive hallux adduction. Results Log transformed data was used to run a paired t-test between the preadduction and postadduction blood flow. The volume of blood flow was 22.2% lower after passive hallux adduction compared to before (− 0.250 ± 0.063, p < 0.001). As AHI decreased, there was a greater negative change in blood flow. As baseline blood flow increased, there was also a greater negative change in blood flow. Conclusions Our preliminary findings of decreased blood flow through passive hallux adduction indicate conditions that elicit passive hallux adduction (e.g. wearing narrow-toed shoes) may have important effects on foot blood flow. Individuals with lower AHI appear to have a greater risk of decreased blood flow with passive hallux adduction.

Validation of fluorescent-labeled microspheres for measurement of relative blood flow in severely injured lungs

1999 ◽  
Vol 87 (6) ◽  
pp. 2381-2385 ◽  
Author(s):  
Matthias Hübler ◽  
Jennifer E. Souders ◽  
Erin D. Shade ◽  
Michael P. Hlastala ◽  
Nayak L. Polissar ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oleic Acid ◽  
Lung Injury ◽  
Scintillation Counter ◽  
Severely Injured ◽  
Flow Measurements ◽  
Fluorescent Microsphere ◽  
Before And After ◽  
Microsphere Method ◽  
Blood Flow Measurements

The aim of the study was to validate a nonradioactive method for relative blood flow measurements in severely injured lungs that avoids labor-intensive tissue processing. The use of fluorescent-labeled microspheres was compared with the standard radiolabeled-microsphere method. In seven sheep, lung injury was established by using oleic acid. Five pairs of radio- and fluorescent-labeled microspheres were injected before and after established lung injury. Across all animals, 175 pieces were selected randomly. The radioactivity of each piece was determined by using a scintillation counter. The fluorescent dye was extracted from each piece with a solvent without digestion or filtering. The fluorescence was determined with an automated fluorescent spectrophotometer. Perfusion was calculated for each piece from both the radioactivity and fluorescence and volume normalized. Correlations between flow determined by the two methods were in the range from 0.987 ± 0.007 (SD) to 0.991 ± 0.002 (SD) after 9 days of soaking. Thus the fluorescent microsphere technique is a valuable tool for investigating regional perfusion in severely injured lungs and can replace radioactivity.

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