Spatial heterogeneity of local blood flow and metabolite content in dog hearts

1988 ◽  
Vol 254 (2) ◽  
pp. H344-H353 ◽  
Author(s):  
D. Franzen ◽  
R. S. Conway ◽  
H. Zhang ◽  
E. H. Sonnenblick ◽  
C. Eng
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Spatial Heterogeneity ◽  
Correlation Coefficients ◽  
Left Ventricular ◽  
Local Blood Flow ◽  
Flow Measurements ◽  
Closed Chest ◽  
Open Chest ◽  
Metabolite Content

Spatial variation (heterogeneity) of myocardial blood flow was studied under basal conditions in relation to four biochemical markers: creatine kinase (CK), lactate dehydrogenase (LDH), ATP, and glycogen. A total of 508 individual 0.5-g samples from the left ventricular free wall was studied in 12 dogs. Myocardial blood flow was measured by radioactive microspheres (15 micron diam) injected via a pigtail catheter into the left ventricle during light sedation (closed-chest flow measurements); following thoracotomy, a second set of microspheres was injected via a catheter into the left atrium (open-chest flow measurements, n = 5). In 27-54 samples/heart, myocardial blood flow, CK, LDH, protein, ATP, and glycogen were determined, permitting a direct correspondence between local blood flow and metabolic markers in each sample and an assessment of the spatial heterogeneity of flow and metabolite content. Correlations between myocardial blood flow per gram tissue and metabolite concentration per gram tissue in pooled data were weak but significant: partial correlation coefficients were 0.137 for CK (P = 0.024), 0.167 for LDH (P = 0.006), 0.341 for ATP (P less than 0.001), 0.123 for glycogen (P = 0.053), but not significant for protein vs. myocardial blood flow. The coefficient of variation, which defines the extent of spatial heterogeneity, averaged 20% for closed-chest flow measurements, 19% for open-chest flow measurements, 22% for CK, 17% for LDH, 15% for protein, 8% for ATP, and 18% for glycogen; these values are over and above the variability due to the technique error, indicating a definite physiological spatial variability. The correlation between local blood flow and the studied metabolites can only explain a minor portion of the spatial heterogeneity of myocardial blood flow. Although a physiological link between blood flow and metabolite content for small regions of the heart is demonstrated, the true local variability of blood flow may be modulated predominantly by other factors.

scholarly journals Ultrasound study of layer-specific strain and perfusion of left ventricular myocardium in patients with dilated cardiomyopathy

2021 ◽  
Author(s):  
Sha Tang ◽  
Lina Guan ◽  
Yuming Mu
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Dilated Cardiomyopathy ◽  
Correlation Coefficients ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Volume Index ◽  
Control Group ◽  
Left Ventricular Myocardium ◽  
Myocardial Microcirculation

Abstract Purpose To investigate the changes in deformation and myocardial microcirculation perfusion of left ventricular three-layer myocardium in patients with dilated cardiomyopathy (DCM) by using speckle tracking imaging (STI) and myocardial contrast echocardiography (MCE). Methods Twenty-four patients with DCM and 19 healthy controls were selected. Two-dimensional and MCE dynamic images of apical four-chamber, two-chamber, and three-chamber sections and left ventricular mitral valve, papillary muscle and apex sections were collected. The peak values of longitudinal strain (LS), circumferential strain (CS), cross-sectional area of a microvessel (A) and average myocardial microvascular lesion (β) were obtained by Qlab 10.8 workstation values, and myocardial blood flow (MBF) was calculated with A × β to evaluate the deformation and coronary microvascular perfusion of left ventricular three-layer myocardium. Results The brain natriuretic peptide (BNP), left ventricular mass index (LVMI), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVEDS), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left atrial volume index (LAVI), E peak in early diastolic period/A peak velocity in late diastolic period (E/A) and average E/e' in the DCM group were higher than those in the control group (P < 0.05); left ventricular ejection fraction (LVEF), left ventricular fractional shortening (FS) rate, stroke volume (SV), cardiac output (CO), cardiac index (CI), A peak, and the e' and a' velocities of both the lateral wall and interventricular septum were smaller than those in the control group (P < 0.05). The LS, CS, A, β, and A × β of the DCM group were all lower than those of the control group, The time to peak and the cardiac cycle required to reach the peak were longer than those in the control group (P < 0.05). The pattern of myocardial strain and perfusion among myocardial layers was subendocardial > middle > subepicardial. The correlation coefficients of LS with A, β, and A × β were − 0.500, -0.279 and − 0.190, respectively, and the correlation coefficients of CS with A, β, and A × β were − 0.383, -0.255 and − 0.208, respectively. Conclusions The deformation of the three-layer myocardium and coronary microcirculation perfusion in DCM patients were diffusely damaged from the endocardium to the epicardium, layer by layer. The longitudinal function of the left ventricular myocardium was closely related to changes in myocardial microcirculation perfusion. Echocardiography is helpful to evaluate myocardial blood flow and myocardial ischemia in patients with DCM.

Coronary collateral stimulation by exercise in dogs with stenotic coronary arteries

1982 ◽  
Vol 52 (3) ◽  
pp. 664-671 ◽  
Author(s):  
M. V. Cohen ◽  
T. Yipintsoi ◽  
J. Scheuer
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Left Atrial ◽  
Reactive Hyperemia ◽  
Left Ventricular ◽  
Treadmill Running ◽  
Collateral Flow ◽  
Flow Measurements ◽  
Collateral Development ◽  
Coronary Collateral

To determine the effects of an exercise-training program on coronary collateral development, we instrumented 13 1-yr-old beagles with left circumflex (LCf) coronary artery flow probes and balloon occluders and left atrial and aortic catheters. The LCf artery was constricted resulting in a 58 +/- 4% reduction of the peak reactive hyperemia response following release of a 154-s LCf occlusion. All dogs were studied during the first week of the study protocol. Resting heart rate, cardiac output, and left atrial and aortic pressures were evaluated before and during a 1-min LCf occlusion. Myocardial blood flow was also measured with radioactively-labeled microspheres injected into the left atrium during the LCf occlusion. Subsequently the dogs were exercised at 6.4 km/h and 12% grade, and all hemodynamic and blood flow measurements were repeated. The animals were then randomized to either a sedentary or exercising group. The six sedentary animals were confined to their cages, while the seven training beagles did sprint and endurance running for 75 min/day, 5 days/wk. After 12 wk the hemodynamic and blood flow studies were repeated at rest and during treadmill running. There were no statistically significant differences in resting or exercise hemodynamics, response to LCf occlusion, or myocardial blood flow in the two groups in wk 1. Hemodynamics and blood flow data were virtually unchanged in the sedentary animals after 12 wk. However, the trained dogs demonstrated less evidence of left ventricular failure following LCf occlusion while running and had significantly higher myocardial blood flows. Their resting collateral flow increased from 0.52 +/- 0.16 ml . min-1 . g-1 at wk 1 to 0.90 +/- 0.28 ml . min-1 . g-1 at wk 12 (P less than 0.05), while the ratio of collateral to normal myocardial blood flow increased from 0.46 +/- 0.12 to 0.64 +/- 0.16 (P less than 0.05). Thus chronic exercise can stimulate coronary collateral development, and the enhanced collateral flow has a salutary functional effect.

scholarly journals Midazolam in combination with fentanyl/fluanisone and nitrous oxide as anaesthesia in rabbits-cardiovascular parameters

1995 ◽  
Vol 29 (4) ◽  
pp. 400-406 ◽  
Author(s):  
Erik Hexeberg ◽  
Sofie Hexeberg ◽  
Idar Hessevik ◽  
Richard T. Fosse
Keyword(s):  
Blood Flow ◽  
Nitrous Oxide ◽  
Left Ventricle ◽  
Femoral Vein ◽  
Rabbit Model ◽  
Left Ventricular ◽  
Tissue Blood Flow ◽  
Cardiovascular Parameters ◽  
Closed Chest ◽  
Open Chest

When establishing a rabbit model for cardiovascular research in our laboratory we have used midazolam in combination with fentanyl/fluanisone (MFF) and nitrous oxide as anaesthesia. In this study we focused on the effect of the anaesthetic regimen on cardiovascular parameters during open-chest surgery in 12 rabbits. Rabbits were tranquillized by intramuscular injection of fentanyl/fluanisone (0.2 ml/kg of the drug that contained 10 mg/ml fentanyl and 0.2 mg/ml fluanisone). After an intraperitoneal injection of midazolam (4 mg/kg) and additional i.m. injection of fentanyl/fluanisone (0.1 ml/kg) the rabbits were tracheotomized and ventilated on a respirator delivering a gas mixture of 50% N2O, 47.5% O2, and 2.5% CO2. The femoral vein and artery were cannulated and then rabbits received a supply of MFF intravenously. The chest was opened by midline sternotomy and the left ventricle was instrumented with piezo-electric crystals for measurement of regional left ventricular function and with a pressure catheter to measure left ventricular pressure. Radiolabelled microspheres were used to assess cardiac output and left ventricular tissue blood flow. Blood gas analysis showed no difference in the values of pH, pCO2 and pO2 between the open-chest and the closed-chest states. Mean aortic pressure was 74 ± 4 mmHg in the closed-chest state and 65 ± 4 mmHg in the open-chest state. Tissue blood flow showed that the left ventricle was well perfused, and mean tissue blood flow values varied between 1.80 and 2.36 ml/min·g. We conclude that the anaesthetic regimen used is easy to control. It is well tolerated in rabbits and is suitable for studies on myocardial contraction in rabbits.

An approach for comparative quantification of myocardial blood flow (0-15-H2O-PET), perfusion (Tc-99m-tetrofosmin-SPECT), and metabolism (F 18-FDG-PET)

2001 ◽  
Vol 40 (05) ◽  
pp. 164-171 ◽  
Author(s):  
B. Nowak ◽  
H.-J. Kaiser ◽  
S. Block ◽  
K.-C. Koch ◽  
J. vom Dahl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Fdg Pet ◽  
Model Fitting ◽  
Compartment Model ◽  
Left Ventricular ◽  
Short Axis ◽  
New Approach ◽  
Single Compartment Model ◽  
Tissue Fraction

Summary Aim: In the present study a new approach has been developed for comparative quantification of absolute myocardial blood flow (MBF), myocardial perfusion, and myocardial metabolism in short-axis slices. Methods: 42 patients with severe CAD, referred for myocardial viability diagnostics, were studied consecutively with 0-15-H2O PET (H2O-PET) (twice), Tc-99m-Tetrofosmin 5PECT (TT-SPECT) and F-18-FDG PET (FDG-PET). All dato sets were reconstructed using attenuation correction and reoriented into short axis slices. Each heart was divided into three representative slices (base, rnidventricular, apex) and 18 ROIs were defined on the FDG PET images and transferred to the corresponding H2O-PET and TT-SPECT slices. TT-SPECT and FDG-PET data were normalized to the ROI showing maximum perfusion. MBF was calculated for all left-ventricular ROIs using a single-compartment-model fitting the dynamic H2O-PET studies. Microsphere equivalent MBF (MBF_micr) was calculated by multiplying MBF and tissue-fraction, a parameter which was obtained by fitting the dynamic H2O-PET studies. To reduce influence of viability only well perfused areas (>70% TT-SPECT) were used for comparative quantification. Results: First and second mean global MBF values were 0.85 ml × min-1 × g-1 and 0.84 ml × min-1 × g1, respectively, with a repeatability coefficient of 0.30 ml ÷ min-1 × gl. After sectorization mean MBF_micr was between 0.58 ml × min1 ÷ ml"1 and 0.68 ml × min-1 × ml"1 in well perfused areas. Corresponding TT-SPECT values ranged from 83 % to 91 %, and FDG-PET values from 91 % to 103%. All procedures yielded higher values for the lateral than the septal regions. Conclusion: Comparative quantification of MBF, MBF_micr, TT-SPECT perfusion and FDG-PET metabolism can be done with the introduced method in short axis slices. The obtained values agree well with experimentally validated values of MBF and MBF_micr.

Myocardial blood flow determined with krypton 85 in unanesthetized dogs

1962 ◽  
Vol 203 (1) ◽  
pp. 122-124 ◽  
Author(s):  
J. A. Herd ◽  
M. Hollenberg ◽  
G. D. Thorburn ◽  
H. H. Kopald ◽  
A. C. Barger
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Myocardial Blood Flow ◽  
Exponential Function ◽  
Scintillation Detector ◽  
Left Ventricular ◽  
Blood Flows ◽  
Single Exponential Function ◽  
Single Exponential ◽  
Rapid Measurements

Serial, rapid measurements of left ventricular myocardial blood flow in trained, unanesthetized dogs have been made by injecting krypton 85 through chronically implanted coronary artery catheters and counting with an external scintillation detector. Precordial radioactivity declined as a single exponential function during the first 2 min after injection, suggesting a single rate of myocardial blood flow. Simultaneous estimations with Kr85 and blood flowmeters in acute experiments established the accuracy and reproducibility of the technique. Myocardial blood flows between 40 and 55 ml/100 g/min were observed repeatedly in three well-trained, unanesthetized dogs in the basal state.

scholarly journals Leaning during chest compressions impairs cardiac output and left ventricular myocardial blood flow in piglet cardiac arrest

2010 ◽  
Vol 38 (4) ◽  
pp. 1141-1146 ◽  
Author(s):  
Mathias Zuercher ◽  
Ronald W. Hilwig ◽  
James Ranger-Moore ◽  
Jon Nysaether ◽  
Vinay M. Nadkarni ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Arrest ◽  
Cardiac Output ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Chest Compressions

Alteration in myocardial oxygen balance during exercise after beta-adrenergic blockade in dogs

1980 ◽  
Vol 49 (1) ◽  
pp. 28-33 ◽  
Author(s):  
G. R. Heyndrickx ◽  
J. L. Pannier ◽  
P. Muylaert ◽  
C. Mabilde ◽  
I. Leusen
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Myocardial Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Sinus ◽  
Myocardial Oxygen Consumption ◽  
Left Ventricular ◽  
Adrenergic Blockade ◽  
Oxygen Balance

The effects of beta-adrenergic blockade upon myocardial blood flow and oxygen balance during exercise were evaluated in eight conscious dogs, instrumented for chronic measurements of coronary blood flow, left ventricular pressure, aortic blood pressure, heart rate, and sampling of arterial and coronary sinus venous blood. The administration of propranolol (1.5 mg/kg iv) produced a decrease in heart rate, peak left ventricular (LV) dP/dt, LV (dP/dt/P, and an increase in LV end-diastolic pressure during exercise. Mean coronary blood flow and myocardial oxygen consumption were lower after propranolol than at the same exercise intensity in control conditions. The oxygen delivery-to-oxygen consumption ratio and the coronary sinus oxygen content were also significantly lower. It is concluded that the relationship between myocardial oxygen supply and demand is modified during exercise after propranolol, so that a given level of myocardial oxygen consumption is achieved with a proportionally lower myocardial blood flow and a higher oxygen extraction.

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