Simultaneous regional myocardial blood flows by tritiated water and microspheres

1977 ◽  
Vol 232 (2) ◽  
pp. H173-H190 ◽  
Author(s):  
M. R. Tripp ◽  
W. Meyer ◽  
S. Einzig ◽  
J. J. Leonard ◽  
C. R. Swayze ◽  
...  
Keyword(s):  
Tritiated Water ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Tissue Uptake ◽  
Tissue Samples ◽  
Blood Flows ◽  
Apical Slice ◽  
Myocardial Layers ◽  
Regional Myocardial Blood ◽  
Good Agreement

Regional myocardial blood flow (RMF) was measured simultaneously by use of labeled 8-mum microspheres and the constant-rate infusion of 3H2O in 22 open-chest dogs (Na pentobarbital anesthesia) under markedly different hemodynamic conditions. Following cardiac excision, three adjacent 80-mg tissue samples were taken from the subendocardial, mid-wall, and subepicardial layers of quadrantal left ventricular (LV) segments of the basal and midventricular cardiac slices, and from one segment of the apical slice, totaling 81 samples per LV. RMF was calculated by the microsphere reference-flow technique and by two 3H2O tissue-uptake models. Good agreement between techniques (r=0.9-0.96) was found in comparing flows to the myocardial layers. Using Kety's "single-mixer" model of 3H2O tissue uptake, fairly good agreement was found between techniques in the 80-mg tissue samples; the cofficient of variation from regression was 18.5% which improved markedly to 12.3% when the flow values for each technique were averaged in the three adjacent samples. Analysis of variance showed that flow to the various LV subdivisions (layer, segment, slice) of control animals was heterogeneous.

Regional myocardial blood flow during pericardial tamponade

1984 ◽  
Vol 62 (5) ◽  
pp. 539-543 ◽  
Author(s):  
Gerald C. Taichman ◽  
Paul Byrne ◽  
George V. Forester ◽  
Wilbert J. Keon
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Right Ventricular ◽  
Ventricular Volume ◽  
Pericardial Tamponade ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Pericardial Cavity ◽  
Blood Flows ◽  
Regional Myocardial Blood

The relative changes in myocardial blood flows within different parts of the heart were measured in anaesthetized thoracotomized dogs during and following effusive pericardial tamponade. Blood flows measured in a group of animals bled to the same arterial hypotensive levels served as experimental controls. The results demonstrate that regional myocardial blood flows to all areas were severely reduced during tamponade. Regional differences in the relative responses were evident; right and left atrial flows decreased more than left ventricular or septal flows which in turn decreased more than right ventricular flow. Significant changes in transmural flow distributions were seen as well; on a relative basis, left and right ventricular endocardial flows decreased more than epicardial and the flow within the left side of the septal wall decreased more than the right. Although decreases in aortic pressure and ventricular volumes can account for some of these changes in flow seen in tamponade, alterations in extravascular compression appear to further reduce the myocardial perfusion and may be responsible for the differences in regional responses. In further experiments when the pericardial cavity was drained following 2 h of tamponade, a hyperemic response was seen throughout the heart indicating that the myocardial flow during tamponade may-have been insufficient to meet the cardiac demands. In conclusion tamponade appears to result in a disproportionate decrease in myocardial blood flow to various parts of the heart which cannot be explained on the basis of a decrease in blood pressure or a reduction in ventricular volume.

Measurement of regional myocardial blood flow in rats by unlabeled microspheres and Coulter channelyzer

1996 ◽  
Vol 271 (4) ◽  
pp. H1656-H1665
Author(s):  
X. Wang ◽  
F. Li ◽  
S. Said ◽  
J. M. Capasso ◽  
A. M. Gerdes
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Cardiac Tissue ◽  
Ex Vivo ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Blood Samples ◽  
Flow Gradients ◽  
Transmural Flow ◽  
Regional Myocardial Blood

A relatively inexpensive, expeditious, new nonradioactive microsphere method for measuring regional myocardial blood flow (RMBF) was developed with unlabeled microspheres and a Coulter Channelyzer. To validate the efficiency of this method, hearts from rats were perfused ex vivo by retrograde aortic cannulation. Unlabeled microspheres of varying size were injected into a side arm in the aortic cannula or added to blood samples collected from the rats. Microspheres were then recovered from the cardiac tissue and blood samples. It was found that > 97% of perfused microspheres (diam > 9.4 microns) were retained in the myocardium and that 94.8 +/- 2.2% of the trapped microspheres were recovered and counted successfully using a Counter Channelyzer. The percent recovery of microspheres from 2- and 0.5-ml blood samples were 95.4 +/- 2.3 and 95.3 +/- 3.1%, respectively. Blood flow to the anterior and posterior halves of the ventricular free walls and septum were measured in six rats; excellent agreements were found between the results yielded by 10-, 15-, and 20-microns unlabeled microspheres injected simultaneously. The transmural flow gradients in the left ventricular free wall estimated by 10- and 15-microns spheres did not significantly differ from each other. Thus the method developed here provides a new alternative for measurement of RMBF, which currently allows at least three measurements for nontransmural gradient RMBF and at least two measurements for transmural gradient RMBF.

Influence of cardiac contraction and coronary vasomotor tone on regional myocardial blood flow

1994 ◽  
Vol 266 (6) ◽  
pp. H2542-H2553 ◽  
Author(s):  
R. E. Austin ◽  
N. G. Smedira ◽  
T. M. Squiers ◽  
J. I. Hoffman
Keyword(s):  
Blood Flow ◽  
Left Ventricular ◽  
Cardiac Contraction ◽  
Regional Myocardial Blood Flow ◽  
Vasomotor Tone ◽  
Coronary Pressure ◽  
Regional Flow ◽  
Anesthetized Dogs ◽  
Coronary Tone ◽  
Regional Myocardial Blood

We analyzed patterns of left ventricular perfusion in arrested hearts without coronary tone and in the same hearts while beating with and without coronary tone. We used microspheres in anesthetized dogs to measure blood flow in 384 regions (averaging 140 mg wet wt) from the subendocardium, midwall, and subepicardium before and during intracoronary infusions of adenosine (beating without tone) or lidocaine and adenosine (arrest without tone). Mean coronary pressure was held constant at 80 mmHg. Changes in regional flow with arrest (vs. beating without tone) were surprisingly variable (range -28 to +124%) and exhibited substantial within-layer heterogeneity, suggesting that local differences in contractility, stresses, or strains limit maximum coronary flow. Regional flows in beating hearts with tone did not correlate with flows in the same hearts without tone, beating or not (r2 < or = 0.03; not significant). Flow patterns during beating with tone also demonstrated significantly shorter (i.e., the distance at which autocorrelation has decreased to 0.5) within-layer spatial autocorrelations as well as a complete loss of radial flow correlation (e.g., between corresponding subendocardial and subepicardial regions; r2 = 0.01). Thus neither coronary anatomy (assessed during arrest without tone) nor the mechanical effects of contraction (beating without tone) appear to influence myocardial perfusion when vasomotor tone is present.

Depression of regional blood flow and wall thickening after brief coronary occlusions

1978 ◽  
Vol 234 (6) ◽  
pp. H653-H659 ◽  
Author(s):  
G. R. Heyndrickx ◽  
H. Baig ◽  
P. Nellens ◽  
I. Leusen ◽  
M. C. Fishbein ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Coronary Occlusion ◽  
Reactive Hyperemia ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Wall Thickening ◽  
Flow Ratio ◽  
Systolic Wall Thickening ◽  
Regional Myocardial Blood

The effects of a 15-min coronary occlusion and subsequent reperfusion were investigated in conscious dogs previously instrumented for measurement of left ventricular pressure, dP/dt, regional wall thickening, electrograms, and myocardial blood flow. Coronary occlussion reduced overall left ventricular function only slightly but eliminated systolic wall thickening in the ischemic zone and reduced regional myocardial blood flow in the ischemic zone from 1.04 +/- 0.04 to 0.27 +/- 0.02 ml/min per g and the endo/epi flow ratio from 1.23 +/- 0.04 to 0.44 +/- 0.04, while S-T segment elevation increased from 1.1 +/- 0.3 to 8.2 +/- 0.9 mV. After release of the occlusion, S-T segment elevation disappeared within 1 min while reactive hyperemia in the previously occluded artery and a transient increase in cardiac diastolic wall thickness occurred and then subsided by 15 min. In contrast, systolic wall thickening and the endo/epi flow ratio remained significantly depressed for more than 3 h. Thus reperfusion after a 15 minute coronary occlusion results in a prolonged period of reduced regional myocardial blood flow, particularly in the endocardial layers, which correlates with the prolonged depression of regional myocardial shortening and wall thickening.

Regional myocardial blood flow and glucose utilization during fasting and physiological hyperinsulinemia in humans

2002 ◽  
Vol 282 (5) ◽  
pp. E1163-E1171 ◽  
Author(s):  
Patricia Iozzo ◽  
Panithaya Chareonthaitawee ◽  
Marco Di Terlizzi ◽  
D. John Betteridge ◽  
Ele Ferrannini ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Healthy Subjects ◽  
Regional Distribution ◽  
Lateral Wall ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Positron Emission ◽  
Normal Human ◽  
Regional Myocardial Blood

We investigated the effect of insulin on total and regional myocardial blood flow (MBF) and glucose uptake (MGU) in healthy subjects (50 ± 5 yr) by means of positron emission tomography (PET) with oxygen-15-labeled water (H2 15O) and fluorine-18 labeled fluorodeoxyglucose (18FDG) before and during physiological hyperinsulinemia (40 mU · min−1 · m−2). Twelve male subjects were included in the study. During hyperinsulinemia, MBF increased from 0.91 ± 0.28 to 1.01 ± 0.31 ml · min−1 · g−1 ( n= 7 patients, P = 0.05; n = 112 regions, P < 0.005). Intersubject variability ranged from −3.0 to +41%. MGU increased from 0.11 ± 0.08 ( n = 5) to 0.56 ± 0.08 μmol · min−1 · g−1( P < 0.0001, n = 7). MBF and insulin-mediated MGU were higher in the septum and anterior and lateral wall along short-axis regions of the heart. During hyperinsulinemia, MBF was also higher in the apex and midventricle compared with the base. MBF and MGU were positively correlated before ( r = 0.66, P < 0.0001) and during hyperinsulinemia ( r= 0.24, P < 0.05). These results provide evidence that insulin stimulates MBF in normal human hearts and appears to involve mainly those regions of the heart where insulin-mediated MGU is higher. Furthermore, regional distribution of insulin-stimulated MBF and MGU does not appear to be uniform across the left ventricular wall of healthy subjects.

scholarly journals Modeling regional myocardial flows from residue functions of an intravascular indicator

1996 ◽  
Vol 271 (4) ◽  
pp. H1643-H1655 ◽  
Author(s):  
K. Kroll ◽  
N. Wilke ◽  
M. Jerosch-Herold ◽  
Y. Wang ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Resonance Imaging ◽  
Vascular Volume ◽  
Regional Flow ◽  
Regional Myocardial Blood

The purpose of the present study was to determine the accuracy and the sources of error in estimating regional myocardial blood flow and vascular volume from experimental residue functions obtained by external imaging of an intravascular indicator. For the analysis, a spatially distributed mathematical model was used that describes transport through a multiple-pathway vascular system. Reliability of the parameter estimates was tested by using sensitivity function analysis and by analyzing “pseudodata”: realistic model solutions to which random noise was added. Increased uncertainty in the estimates of flow in the pseudodata was observed when flow was near maximal physiological values, when dispersion of the vascular input was more than twice the dispersion of the microvascular system for an impulse input, and when the sampling frequency was < 2 samples/s. Estimates of regional blood volume were more reliable than estimates of flow. Failure to account for normal flow heterogeneity caused systematic underestimates of flow. To illustrate the method used for estimating regional flow, magnetic resonance imaging was used to obtain myocardial residue functions after left atrial injections of polylysine-Gd-diethylenetriaminepentaacetic acid, an intravascular contrast agent, in anesthetized chronically instrumental dogs. To test the increase in dispersion of the vascular input after central venous injections, magnetic resonance imaging data obtained in human subjects were compared with left ventricular blood pool curves obtained in dogs. It is concluded that if coronary flow is in the normal range, when the vascular input is a short bolus, and the heart is imaged at least once per cardiac cycle, then regional myocardial blood flow and vascular volume may be reliably estimated by analyzing residue functions of an intravascular indicator, providing a noninvasive approach with potential clinical application.

scholarly journals Regional myocardial blood flow and left ventricular diastolic properties in pacing-induced ischemia

1991 ◽  
Vol 17 (3) ◽  
pp. 781-789 ◽  
Author(s):  
Shin-Ichi Momomura ◽  
James J. Ferguson ◽  
Michael J. Miller ◽  
J. Anthony Parker ◽  
William Grossman
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Diastolic Properties ◽  
Regional Myocardial Blood
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