Regional myocardial blood flow during graded treadmill exercise in the dog.

Ball, Richard; Bache, RJ; Cobb, F R; Greenfield, Jr Jc

doi:10.1172/jci107916

Cited by 101 publications

(43 citation statements)

References 15 publications

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“…The numbers of microspheres per 1µL of heart tissue were determined in each region. The mean±SEM ratio of endocardial to epicardial microspheres is 1.33±0.11 (n=11), consistent with observations in dogs [23][24][25] and humans. 26 The serially and simultaneously injected hearts were also virtually dissected into endocardial and epicardial regions, and the numbers of microspheres per 1µL of heart tissue were determined in each region.…”

Section: Mouse Heart Experimentssupporting

confidence: 88%

Visualizing Regional Myocardial Blood Flow in the Mouse

Krueger

Huke

Glenny

2013

Circulation Research

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Rationale:The spatial distribution of blood flow in the hearts of genetically modified mice is a phenotype of interest because derangements in blood flow may precede detectable changes in organ function. However, quantifying the regional distribution of blood flow within organs of mice is challenging because of the small organ volume and the high resolution required to observe spatial differences in flow. Traditional microsphere methods in which the numbers of microspheres per region are indirectly estimated from radioactive counts or extracted fluorescence have been limited to larger organs for 2 reasons; to ensure statistical confidence in the measured flow per region and to be able to physically dissect the organ to acquire spatial information.

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Section: Mouse Heart Experimentssupporting

confidence: 88%

Visualizing Regional Myocardial Blood Flow in the Mouse

Krueger

Huke

Glenny

2013

Circulation Research

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“…Because the reactive hyperemic response is usually attended by a decrease in transmyocardial arteriovenous oxygen difference, one cannot assume that the myocardium, under these conditions, is ischemic. However, during heavy exercise, flow in the endocardial layer in the normal dog was found, in our laboratory, to increase to 3.82+0.3 cm3/min per g which is considerably higher than the endocardial flow of 2.04+±0.25 cm3/min per g found in these dogs with hypertrophy during maximum vasodilatation (23). Thus, in situations requiring high flow to meet the metabolic requirements to the heart, e.g.…”

Section: Resultsmentioning

confidence: 53%

Myocardial Blood Flow Distribution in Concentric Left Ventricular Hypertrophy

Rembert¹,

Kleinman²,

Fedor³

et al. 1978

J. Clin. Invest.

163

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A B S T R A C T Regional myocardial blood flow during both control conditions and ischemia-induced vasodilatation was studied in eight chronically instrumented awake dogs. Seven of these animals had coarctationbanding ofthe ascending aorta performed at 6 wk of age, and the other dog had congenital subvalvular aortic stenosis. The mean left ventricular weight for the group was 157±7.6 g, and the left ventricular body weight ratio was 8.76+0.47 g/kg. None ofthe animals exhibited signs of congestive heart failure.During the control state, the mean left ventricular systolic pressure was 249+12 mm Hg and the left ventricular end-diastolic pressure was 11.5±0.5 mm Hg. The aortic diastolic pressure was 74±6 mm Hg. Mean left circumflex coronary artery blood flow was 71±6 cm3/min. In the animals with coarctation-banding, 52±6% of the flow occurred during systole. In the dog with congenital subvalvular aortic stenosis, 5% of the coronary flow was systolic. Mean transmural blood flow during resting conditions was 0.97±0.08 cm3/min per g, and the ratio of endocardial to epicardial flow (endo/epi) was 0.88±0.07. During reactive hyperemia, the mean transmural blood flow increased to 3.5±0.30 cm3/min per g; however, the endo/epi decreased to 0.52±0.06.These studies document a difference in transmural blood flow distribution between the normal and the hypertrophied left ventricle: during resting conditions, in the normal ventricle, the highest flow occurs in the endocardial layer, whereas in the hypertrophied ventricle, the highest flow is in the middle layers with the endocardial flow less than the epicardial flow.

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“…Previous studies from our laboratory and others have demonstrated that during vasodilation induced by intense exercise (19), and during the reactive hyperemic phase induced by transient ischemia (20) and by vasoactive drugs including adenosine (21) and chromar (22), myocardial blood flow increases fourto sixfold. These studies have indicated that during maximum or near-maximum vasodilation, blood flow is markedly increased in each layer and the endo/epi blood flow ratio usually remains near 1.0.…”

Section: Discussionmentioning

confidence: 89%

Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation.

Mays¹,

Cobb²

1984

J. Clin. Invest.

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Abstract. This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured.Curvilinear regression analyses between thallium-20 1 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second-as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood This work was presented in part at the 54th Scientific Session of the American Heart Association, November 1981, Dallas, Texas.Received for publication 7 January 1983 and in revised form 16 January 1984. flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-20 1 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow.

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Regional myocardial blood flow during graded treadmill exercise in the dog.

Cited by 101 publications

References 15 publications

Visualizing Regional Myocardial Blood Flow in the Mouse

Visualizing Regional Myocardial Blood Flow in the Mouse

Myocardial Blood Flow Distribution in Concentric Left Ventricular Hypertrophy

Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation.

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