Importance of injection site for coronary blood flow determinations by microspheres in rats

1982 ◽  
Vol 242 (1) ◽  
pp. H94-H97 ◽  
Author(s):  
P. Wicker ◽  
R. C. Tarazi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Injection Site ◽  
Coronary Blood Flow ◽  
Left Atrial ◽  
Left Ventricular ◽  
Significant Difference ◽  
Standard Deviations

Because coronary blood flow (CBF) determinations require that blood and microspheres be uniformly mixed in the root of the aorta, we developed a technique of left-atrial (LA) catheterization in rats and compared the variability of results obtained by LA injection and left-ventricular (LV) injection as regards systemic [cardiac output (CO)], proximal (coronary), and distal (renal, cerebral) flows in anesthetized animals. CBF values averaged 410 +/- 224 and 358 +/- 99 (SD) ml.min-1.100 g-1 from LV and LA injection, respectively, or 5.7 +/- 2.9 and 4.9 +/- 1.3 (SD) %CO. The variability with LA injection was significantly lower than with LV injection as shown by the marked differences in standard deviations obtained with the two methods (224 vs. 99 ml.min-1.100 g-1 or 2.9 vs. 1.3 %CO, P greater than 0.01). In contrast, no significant difference in variability was found for either CO or more distal regional flows. These results indicate that LV injections might be adequate for systemic flow and regional flows to relatively distal beds but that accurate measurements of CBF require LA injection of microspheres.

Effects of intensive exercise training on myocardial performance and coronary blood flow

1980 ◽  
Vol 49 (3) ◽  
pp. 444-449 ◽  
Author(s):  
R. J. Barnard ◽  
H. W. Duncan ◽  
K. M. Baldwin ◽  
G. Grimditch ◽  
G. D. Buckberg
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Work Capacity ◽  
Left Ventricular ◽  
Maximum Exercise ◽  
Time Index ◽  
Significant Difference ◽  
Tension Time

Five instrumented and eight noninstrumented dogs were progressively trained for 12-18 wk on a motor-driven treadmill. Data were compared with 14 instrumented and 8 noninstrumented control dogs. Gastrocnemius malate dehydrogenase activity was significantly increased in the trained dogs (887 +/- 75 vs. 667 +/- 68 mumol . g-1 . min-1). The trained dogs also showed significant increases in maximum work capacity, cardiac output (7.1 +/- 0.5 vs. 9.1 +/- 0.7 1/min), stroke volume (25.9 +/- 2.0 vs. 32.0 +/- 2.0 ml/beat), and left ventricular (LV) positive dP/dtmax (9,242 +/- 405 vs. 11,125 +/- 550 Torr/s). Negative dP/dtmax was not significantly different. Peak LV systolic pressure increased with exercise, but there was no significant difference between the trained and control dogs. LV end-diastolic pressure did not change with exercise and was the same in both groups. Tension-time index was lower in the trained dogs at rest and submaximum exercise (9.7 km/h, 10%) but was not different at maximum exercise. Diastolic pressure-time index was significantly higher in the trained dogs at rest and during submaximum exercise but was not different at maximum exercise. LV coronary blood flow was significantly reduced at rest (84 +/- 4 vs. 67 +/- 6 mo . min-1 . 100 g-1) and during submaximum exercise (288 +/- 24 vs. 252 +/- 8 ml . min-1 . 100 g-1). During maximum exercise flow was not significantly different (401 +/- 22 vs. 432 +/- 11 ml . min-1 . 100 g-1) between the control and trained groups. The maximum potential for subendocardial flow was unchanged with training despite the development of mild hypertrophy.

Adrenomedullin-epinephrine cotreatment enhances cardiac output and left ventricular function by energetically neutral mechanisms

2012 ◽  
Vol 302 (8) ◽  
pp. H1584-H1590
Author(s):  
Thor Allan Stenberg ◽  
Anders Benjamin Kildal ◽  
Ole-Jakob How ◽  
Truls Myrmel
Keyword(s):  
Heart Failure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Acute Heart Failure ◽  
Coronary Blood Flow ◽  
Drug Effects ◽  
Left Ventricular ◽  
Experimental Myocardial Infarction ◽  
Energetic Cost ◽  
Lv Function

Adrenomedullin (AM) used therapeutically reduces mortality in the acute phase of experimental myocardial infarction. However, AM is potentially deleterious in acute heart failure as it is vasodilative and inotropically neutral. AM and epinephrine (EPI) are cosecreted from chromaffin cells, indicating a physiological interaction. We assessed the hemodynamic and energetic profile of AM-EPI cotreatment, exploring whether drug interaction improves cardiac function. Left ventricular (LV) mechanoenergetics were evaluated in 14 open-chest pigs using pressure-volume analysis and the pressure-volume area-myocardial O2 consumption (PVA-MV˙o2) framework. AM (15 ng·kg−1·min−1, n = 8) or saline (controls, n = 6) was infused for 120 min. Subsequently, a concurrent infusion of EPI (50 ng·kg−1·min−1) was added in both groups (AM-EPI vs. EPI). AM increased cardiac output (CO) and coronary blood flow by 20 ± 10% and 39 ± 14% (means ± SD, P < 0.05 vs. baseline), whereas controls were unaffected. AM-EPI increased CO and coronary blood flow by 55 ± 17% and 75 ± 16% ( P < 0.05, AM-EPI interaction) compared with 13 ± 12% ( P < 0.05 vs. baseline) and 18 ± 31% ( P = not significant) with EPI. LV systolic capacitance decreased by −37 ± 22% and peak positive derivative of LV pressure (dP/d tmax) increased by 32 ± 7% with AM-EPI ( P < 0.05, AM-EPI interaction), whereas no significant effects were observed with EPI. Mean arterial pressure was maintained by AM-EPI and tended to decrease with EPI (+2 ± 13% vs. −11 ± 10%, P = not significant). PVA-MV˙o2 relationships were unaffected by all treatments. In conclusion, AM-EPI cotreatment has an inodilator profile with CO and LV function augmented beyond individual drug effects and is not associated with relative increases in energetic cost. This can possibly take the inodilator treatment strategy beyond hemodynamic goals and exploit the cardioprotective effects of AM in acute heart failure.

Effects of metabolic acidosis and alkalosis on coronary blood flow and myocardial metabolism in the intact dog

1961 ◽  
Vol 200 (3) ◽  
pp. 628-632 ◽  
Author(s):  
A. V. N. Goodyer ◽  
W. F. Eckhardt ◽  
R. H. Ostberg ◽  
M. J. Goodkind
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Metabolic Acidosis ◽  
Coronary Blood Flow ◽  
Venous Blood ◽  
Left Ventricular ◽  
Myocardial Uptake ◽  
Severe Metabolic Acidosis ◽  
Glucose Levels ◽  
Arterial Blood

Severe metabolic acidosis and alkalosis were induced in anesthetized dogs by the infusion of solutions of hydrochloric acid and sodium bicarbonate. Infusions of sodium chloride were administered to other dogs under the same experimental circumstances. Measurements were made of arterial blood pressure, heart rate, cardiac output and coronary blood flow, arterial blood pH, and the content of oxygen, total CO2, lactate, pyruvate and glucose in both arterial and coronary venous blood. The cardiac output and coronary blood flow were decreased by acidosis and increased by alkalosis, the changes induced by alkalosis. There were no significant changes of left ventricular efficiency. Acidosis increased blood glucose concentrations and interfered with the increased myocardial uptake of glucose expected at higher arterial glucose levels. Alkalosis increased blood lactate and pyruvate levels and, correspondingly, the myocardial uptake of these carbohydrate substrates. It is concluded that cardiac dynamic function (as indicated by measurements of cardiac efficiency and output and arterial pressure) is much less affected by severe metabolic acidosis in the intact animal than in the isolated perfused organ.

Coronary flow by left atrial and left ventricular microsphere injection in the rat

1990 ◽  
Vol 259 (2) ◽  
pp. H635-H638
Author(s):  
G. D. Schrock ◽  
R. L. Krahmer ◽  
J. L. Ferguson
Keyword(s):  
Blood Flow ◽  
Left Ventricle ◽  
Left Atrium ◽  
Coronary Blood Flow ◽  
Left Atrial ◽  
Blood Gases ◽  
Left Ventricular ◽  
Systemic Blood ◽  
Systemic Blood Flow ◽  
Blood Flows

Previous studies have reported significantly higher variability in coronary blood flow (CBF) measurements obtained by microsphere injection into the left ventricle (LV) as compared with microsphere injection into the left atrium (LA) of the rat. Questions have arisen concerning whether or not some of the variability may have been due to successive rather than simultaneous injections at the two sites, thereby giving measurements at different cardiovascular states. To address this question, we measured cardiac output (CO) and CBF as well as other systemic organ blood flows by employing simultaneous injection of two different sets of radiolabeled microspheres into the left atrium and left ventricle of semiconscious rats. Using this technique, CBF values (ml.min-1.g-1) of 5.45 +/- 0.43 and 5.24 +/- 0.46 for LA and LV injection sites, respectively, were measured (all values reported as means +/- SE). CO values (ml/min) of 67.5 +/- 3.5 for LA and 67.6 +/- 3.4 for LV were obtained. Paired left atrial and left ventricular measurements of CBF, CO, and other systemic organ blood flows using tracer microsphere methodology were not significantly different. All variabilities in these measurements by LA and LV injection were not significantly different. Our procedure did not significantly alter physiological parameters such as heart rate, mean arterial pressure, hematocrit, or blood gases. These findings indicate that, in our rat model, measurements made by LV microsphere injection are not only adequate for determining systemic blood flow at distal beds but provide coronary blood flow data with variability not significantly different from that of left atrial injection.

scholarly journals Head-up suspension in humans: effects on sympathetic vasomotor activity and cardiovascular responses

1998 ◽  
Vol 84 (5) ◽  
pp. 1513-1519 ◽  
Author(s):  
A. S. M. Shamsuzzaman ◽  
Y. Sugiyama ◽  
A. Kamiya ◽  
Q. Fu ◽  
T. Mano
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Left Atrial ◽  
Muscle Sympathetic Nerve Activity ◽  
Cardiovascular Responses ◽  
Left Atrial Diameter ◽  
Calf Blood Flow ◽  
Significant Difference

We hypothesized that muscle sympathetic nerve activity (MSNA) and cardiovascular responses to the conventional head-up tilt (HUT) are different from those to head-up suspension (HUS) because of antigravity muscle activity. The MSNA from the tibial nerve, heart rate, blood pressure, stroke volume, cardiac output, and calf blood flow were measured in 13 healthy young subjects. Left atrial diameter was measured by two-dimensional echocardiography in another nine subjects. The resting MSNA and cardiovascular responses at a low level (20°) of orthostasis were similar during both modes. At higher levels (40 and 60°), the responses of MSNA, heart rate, stroke volume, and cardiac output were significantly stronger and there was a smaller reduction in calf blood flow during HUT than during HUS ( P < 0.05). Left atrial diameter was decreased significantly from the resting values during HUT and HUS without any significant difference between the modes of orthostasis. The results provide evidence that the engagement of antigravity muscles during HUT may have additive effects on sympathetic vasoconstrictor and cardiovascular responses to orthostatic stress.

Effects of Elevated Coronary Sinus Pressure on Coronary Blood Flow and Left Ventricular Function

Circulation ◽  
1995 ◽  
Vol 92 (9) ◽  
pp. 298-303 ◽  
Author(s):  
Takuya Miura ◽  
Takeshi Hiramatsu ◽  
Joseph M. Forbess ◽  
John E. Mayer
Keyword(s):  
Blood Flow ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Coronary Blood Flow ◽  
Coronary Sinus ◽  
Left Ventricular ◽  
Sinus Pressure

Contribution of extravascular compression to reduction of maximal coronary blood flow

1992 ◽  
Vol 262 (1) ◽  
pp. H68-H77
Author(s):  
F. L. Abel ◽  
R. R. Zhao ◽  
R. F. Bond
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Flow ◽  
Perfusion Pressure ◽  
Left Ventricular Pressure ◽  
Coronary Perfusion Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Coronary Perfusion ◽  
Storage Site

Effects of ventricular compression on maximally dilated left circumflex coronary blood flow were investigated in seven mongrel dogs under pentobarbital anesthesia. The left circumflex artery was perfused with the animals' own blood at a constant pressure (63 mmHg) while left ventricular pressure was experimentally altered. Adenosine was infused to produce maximal vasodilation, verified by the hyperemic response to coronary occlusion. Alterations of peak left ventricular pressure from 50 to 250 mmHg resulted in a linear decrease in total circumflex flow of 1.10 ml.min-1 x 100 g heart wt-1 for each 10 mmHg of peak ventricular to coronary perfusion pressure gradient; a 2.6% decrease from control levels. Similar slopes were obtained for systolic and diastolic flows as for total mean flow, implying equal compressive forces in systole as in diastole. Increases in left ventricular end-diastolic pressure accounted for 29% of the flow changes associated with an increase in peak ventricular pressure. Doubling circumferential wall tension had a minimal effect on total circumflex flow. When the slopes were extrapolated to zero, assuming linearity, a peak left ventricular pressure of 385 mmHg greater than coronary perfusion pressure would be required to reduce coronary flow to zero. The experiments were repeated in five additional animals but at different perfusion pressures from 40 to 160 mmHg. Higher perfusion pressures gave similar results but with even less effect of ventricular pressure on coronary flow or coronary conductance. These results argue for an active storage site for systolic arterial flow in the dilated coronary system.

scholarly journals Anesthetic Techniques for Fetal Surgery

2013 ◽  
Vol 118 (4) ◽  
pp. 796-808 ◽  
Author(s):  
Pornswan Ngamprasertwong ◽  
Erik C. Michelfelder ◽  
Shahriar Arbabi ◽  
Yun Suk Choi ◽  
Christopher Statile ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Function ◽  
Fetal Surgery ◽  
Left Ventricular ◽  
High Dose ◽  
Anesthetic Techniques ◽  
Uterine Blood Flow ◽  
Fetal Cardiac Function ◽  
Significant Difference ◽  
Fetal Acidosis

Abstract Background: Use of high-dose inhalational anesthesia during open fetal surgery may induce maternal–fetal hemodynamic instability and fetal myocardial depression. The authors’ preliminary human retrospective study demonstrated less fetal bradycardia and left ventricular systolic dysfunction with lower dose desflurane supplemented with propofol and remifentanil IV anesthesia (SIVA). In this animal study, the authors compare maternal–fetal effects of high-dose desflurane anesthesia (HD-DES) and SIVA. Methods: Of 26 instrumented midgestational ewes, data from 11 animals exposed to both SIVA and HD-DES in random sequences and six animals exposed to HD-DES while maternal normotension was maintained were analyzed. Maternal electroencephalography was used to guide comparable depths of anesthesia in both techniques. Hemodynamic parameters, blood gas, and fetal cardiac function from echocardiography were recorded. Results: Compared with SIVA, HD-DES resulted in significant maternal hypotension (mean arterial pressure difference, 19.53 mmHg; 95% CI, 17.6–21.4; P &lt; 0.0001), fetal acidosis (pH 7.11 vs. 7.24 at 150 min, P &lt; 0.001), and decreased uterine blood flow. In the HD-DES group with maternal normotension, uterine blood flow still declined and fetal acidosis persisted, with no statistically significant difference from the group exposed to HD-DES that had maternal hypotension. There was no statistically significant difference in fetal cardiac function. Conclusion: In sheep, SIVA affects maternal hemodynamics less and provides better fetal acid/base status than high-dose desflurane. Fetal echocardiography did not reflect myocardial dysfunction in this model.

alpha-Adrenergic control of oxygen delivery to myocardium during exercise in conscious dogs

1982 ◽  
Vol 242 (5) ◽  
pp. H805-H809 ◽  
Author(s):  
G. R. Heyndrickx ◽  
P. Muylaert ◽  
J. L. Pannier
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Coronary Blood Flow ◽  
Coronary Sinus ◽  
Oxygen Delivery ◽  
Left Ventricular ◽  
Conscious Dogs ◽  
Adrenergic Blockade ◽  
Adrenergic Control

alpha-Adrenergic control of the oxygen delivery to the myocardium during exercise was investigated in eight conscious dogs instrumented for chronic measurements of coronary blood flow, left ventricular (LV) pressure, aortic blood pressure, and heart rate and sampling of arterial and coronary sinus blood. After alpha-adrenergic receptor blockade a standard exercise load elicited a significantly greater increase in heart rate, rate of change of LV pressure (LV dP/dt), LV dP/dt/P, and coronary blood flow than was elicited in the unblocked state. In contrast to the response pattern during control exercise, there was no significant change in coronary sinus oxygen tension (PO2), myocardial arteriovenous oxygen difference, and myocardial oxygen delivery-to-oxygen consumption ratio. It is concluded that the normal relationship between myocardial oxygen supply and oxygen demand is modified during exercise after alpha-adrenergic blockade, whereby oxygen delivery is better matched to oxygen consumption. These results indicate that the increase in coronary blood flow and oxygen delivery to the myocardium during normal exercise is limited by alpha-adrenergic vasoconstriction.

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