Prediction of Stroke Volume From Oxygen Pulse Measurements in Untrained and Trained Men

1994 ◽  
Vol 19 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Yagesh Bhambhani ◽  
Stephen Norris ◽  
Gordon Bell
Keyword(s):  
Stroke Volume ◽  
Stroke Volume Index ◽  
Volume Index ◽  
Regression Equations ◽  
Cycle Exercise ◽  
Oxygen Pulse ◽  
Difference Formula ◽  
Relationship Of ◽  
The Relationship ◽  
Oxygen Difference

This study examined the relationship of oxygen pulse (O2 pulse) to stroke volume (SV) and arterio-venous oxygen difference [[Formula: see text] diff] during submaximal cycle exercise in untrained (UG) and trained (TG) males. Fourteen volunteers in each group completed an incremental [Formula: see text] max test and a submaximal test at 60% [Formula: see text] max to determine cardiac output (Q) via CO2 rebreathing. [Formula: see text], Q, and heart rate (HR) were used to calculate SV and [Formula: see text] diff. There were no significant differences (p >.05) between the two groups for O2 pulse, SV, and [Formula: see text] diff during submaximal exercise. Stroke volume index (SVI) was significantly higher (p <.05) in the TG. O2 pulse was significantly related to SV and SVI (p <.05) but not to [Formula: see text] diff in both groups. Regression equations for predicting SV from O2 pulse for UG and TG were Y = 6.81X + 26.7, SE = 21.4, r = 0.84, and Y = 10.33X - 32.3, SE = 14.2, r = 0.71, respectively. These results suggest that O2 pulse can be used to predict SV during submaximal cycle exercise in untrained and trained men. Key words: cardiac performance, exercise, training status

Impact of age on the cardiovascular response to dynamic upright exercise in healthy men and women

1995 ◽  
Vol 78 (3) ◽  
pp. 890-900 ◽  
Author(s):  
J. L. Fleg ◽  
F. O'Connor ◽  
G. Gerstenblith ◽  
L. C. Becker ◽  
J. Clulow ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Cardiovascular Response ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Cardiac Response ◽  
Volume Index ◽  
Left Ventricular Volumes ◽  
Stroke Work ◽  
Cycle Exercise ◽  
Men And Women

To examine whether age differentially modifies the physiological response to exercise in men and women, we performed gated radionuclide ventriculography with measurement of left ventricular volumes at rest and during peak upright cycle exercise in 200 rigorously screened healthy sedentary volunteers (121 men and 79 women) aged 22–86 yr from the Baltimore Longitudinal Study of Aging. At rest in the sitting position, age-associated declines in heart rate (HR) and increases in systolic blood pressure occurred in both sexes. Whereas resting cardiac index (CI) and total systemic vascular resistance (TSVR) in men did not vary with age, in women resting CI decreased 16% and TSVR increased 46% over the six-decade age span. Men, but not women, demonstrated an age-associated increase of approximately 20% in sitting end-diastolic volume index (EDVI), end-systolic volume index (ESVI), and stroke volume index over this age span. Peak cycle work rate declined with age approximately 40% in both sexes, but at any age it was greater in men than in women even after normalization for body weight. At peak effort, ejection fraction (EF), HR, and CI were reduced similarly with age while ESVI and TSVR were increased in both sexes; EDVI increased 35% with age and stroke work index (SWI) rose 19% in men, but neither was related to age in women; and stroke volume index did not vary with age in either sex. When hemodynamics were expressed as the change from rest to peak effort as an index of cardiovascular reserve function, both sexes demonstrated age-associated increases in EDVI and ESVI and reductions in EF, HR, and CI. However, the exercise-induced reduction in ESVI and the increases in EF, CI, and SWI from rest were greater in men than in women. Thus, age and gender each have a significant impact on the cardiac response to exhaustive upright cycle exercise.

scholarly journals A proof of principle study of atomoxetine for the prevention of vasovagal syncope: the Prevention of Syncope Trial VI

EP Europace ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1733-1741 ◽  
Author(s):  
Robert S Sheldon ◽  
Lucy Lei ◽  
Juan C Guzman ◽  
Teresa Kus ◽  
Felix A Ayala-Paredes ◽  
...  
Keyword(s):  
Cardiac Index ◽  
Stroke Volume ◽  
Vasovagal Syncope ◽  
Resistance Index ◽  
Stroke Volume Index ◽  
Study Drug ◽  
Norepinephrine Transporter ◽  
Volume Index ◽  
Head Up Tilt ◽  
Invasive Techniques

Abstract Aims There are few effective therapies for vasovagal syncope (VVS). Pharmacological norepinephrine transporter (NET) inhibition increases sympathetic tone and decreases tilt-induced syncope in healthy subjects. Atomoxetine is a potent and highly selective NET inhibitor. We tested the hypothesis that atomoxetine prevents tilt-induced syncope. Methods and results Vasovagal syncope patients were given two doses of study drug [randomized to atomoxetine 40 mg (n = 27) or matched placebo (n = 29)] 12 h apart, followed by a 60-min drug-free head-up tilt table test. Beat-to-beat heart rate (HR), blood pressure (BP), and cardiac haemodynamics were recorded using non-invasive techniques and stroke volume modelling. Patients were 35 ± 14 years (73% female) with medians of 12 lifetime and 3 prior year faints. Fewer subjects fainted with atomoxetine than with placebo [10/29 vs. 19/27; P = 0.003; risk ratio 0.49 (confidence interval 0.28–0.86)], but equal numbers of patients developed presyncope or syncope (23/29 vs. 21/27). Of patients who developed only presyncope, 87% (13/15) had received atomoxetine. Patients with syncope had lower nadir mean arterial pressure than subjects with only presyncope (39 ± 18 vs. 69 ± 18 mmHg, P < 0.0001), and this was due to lower trough HRs in subjects with syncope (67 ± 30 vs. 103 ± 32 b.p.m., P = 0.006) and insignificantly lower cardiac index (2.20 ± 1.36 vs. 2.84 ± 1.05 L/min/m2, P = 0.075). There were no significant differences in stroke volume index (32 ± 6 vs. 35 ± 5 mL/m2, P = 0.29) or systemic vascular resistance index (2156 ± 602 vs. 1790 ± 793 dynes*s/cm5*m2, P = 0.72). Conclusion Norepinephrine transporter inhibition significantly decreased the risk of tilt-induced syncope in VVS subjects, mainly by blunting reflex bradycardia, thereby preventing final falls in cardiac index and BP.

Stroke Volume Index and Outcomes in Low-Gradient Severe Aortic Stenosis

2021 ◽  
Vol 30 ◽  
pp. S205
Author(s):  
A. Snir ◽  
M. Ng ◽  
G. Strange ◽  
D. Playford ◽  
S. Stewart ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Stroke Volume ◽  
Severe Aortic Stenosis ◽  
Stroke Volume Index ◽  
Volume Index

Vascular endothelial growth factor-C stimulates the lymphatic pump by a VEGF receptor-3-dependent mechanism

2007 ◽  
Vol 293 (1) ◽  
pp. H709-H718 ◽  
Author(s):  
Jerome W. Breslin ◽  
Nathalie Gaudreault ◽  
Katherine D. Watson ◽  
Rashell Reynoso ◽  
Sarah Y. Yuan ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Stroke Volume Index ◽  
Volume Index ◽  
Flow Index ◽  
Vegf Receptor ◽  
Vascular Endothelial ◽  
Contraction Frequency ◽  
Pump Activity ◽  
Endothelial Growth Factor ◽  
Arteriolar Diameter

Vascular endothelial growth factor (VEGF)-C plays an important role in lymphangiogenesis; however, functional responses of lymphatic vessels to VEGF-C have not been characterized. We tested the hypothesis that VEGF-C-induced activation of VEGF receptor (VEGFR)-3 increases lymphatic pump output. We examined the in vivo pump activity of rat mesenteric collecting lymphatics using intravital microscopy during basal conditions and during treatment with 1 nM recombinant VEGF-C, the selective VEGFR-3 agonist VEGF-Cys156Ser mutation (C156S; 1 nM), or 0.1 nM VEGF-A. Their specific responses were also analyzed during selective inhibition of VEGFR-3 with MAZ-51. Contraction frequency, end-diastolic diameter, end-systolic diameter, stroke volume index, pump flow index, and ejection fraction were evaluated. We also assessed arteriolar diameter and microvascular extravasation of FITC-albumin. The results show that both VEGF-C and VEGF-C156S significantly increased contraction frequency, end-diastolic diameter, stroke volume index, and pump flow index in a time-dependent manner. VEGF-A caused a different response characterized by a significantly increased stroke volume after 30 min of treatment. MAZ-51 (5 μM) caused tonic constriction and decreased contraction frequency. In addition, 0.5 and 5 μM MAZ-51 attenuated VEGF-C- and VEGF-C156S-induced lymphatic pump activation. VEGF-A caused vasodilation of arterioles, whereas VEGF-C and VEGF-C156S did not significantly alter arteriolar diameter. Also, VEGF-A and VEGF-C caused increased microvascular permeability, whereas VEGF-C156S did not. Our results demonstrate that VEGF-C increases lymphatic pumping through VEGFR-3. Furthermore, changes in microvascular hemodynamics are not required for VEGFR-3-mediated changes in lymphatic pump activity.

scholarly journals Stress Echocardiography in Hyperthyroidism

1999 ◽  
Vol 84 (7) ◽  
pp. 2308-2313 ◽  
Author(s):  
George J. Kahaly ◽  
Stephan Wagner ◽  
Jana Nieswandt ◽  
Susanne Mohr-Kahaly ◽  
Thomas J. Ryan
Keyword(s):  
Heart Rate ◽  
Ejection Fraction ◽  
Stroke Volume ◽  
Stress Echocardiography ◽  
Maximal Exercise ◽  
Stroke Volume Index ◽  
Work Load ◽  
Left Ventricular ◽  
Volume Index ◽  
Systolic Volume

Exertion symptoms occur frequently in subjects with hyperthyroidism. Using stress echocardiography, exercise capacity and global left ventricular function can be assessed noninvasively. To evaluate stress-induced changes in cardiovascular function, 42 patients with untreated thyrotoxicosis were examined using exercise echocardiography. Studies were performed during hyperthyroidism, after treatment with propranolol, and after restoration of euthyroidism. Twenty- two healthy subjects served as controls. Ergometry was performed with patients in a semisupine position using a continuous ramp protocol starting at 20 watts/min. In contrast to control and euthyroidism, the change in end-systolic volume index from rest to maximal exercise was lower in hyperthyroidism. At rest, the stroke volume index, ejection fraction, and cardiac index were significantly increased in hyperthyroidism, but exhibited a blunted response to exercise, which normalized after restoration of euthyroidism. Propranolol treatment also led to a significant increase of delta (Δ) stroke volume index. Maximal work load and Δ heart rate were markedly lower in hyper- vs. euthyroidism. Compared to the control value, systemic vascular resistance was lowered by 36% in hyperthyroidism at rest, but no further decline was noted at maximal exercise. The Δ stroke volume index, Δ ejection fraction, Δ heart rate, and maximal work load were significantly reduced in severe hyperthyroidism. Negative correlations between free T3 and diastolic blood pressure, maximal work load, Δ heart rate, and Δ ejection fraction were noted. Thus, in hyperthyroidism, stress echocardiography revealed impaired chronotropic, contractile, and vasodilatatory cardiovascular reserves, which were reversible when euthyroidism was restored.

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