Neuromodulation therapy does not influence blood flow distribution or left-ventricular dynamics during acute myocardial ischemia

To characterize the mechanisms for myocardial ischemia induced by hemorrhagic shock, 29 dogs were subjected to hemorrhage at a mean aortic pressure (MAoP) of 30-60 mmHg. After 10 min of hemorrhage, the beating hearts were rapidly cross sectioned and freeze clamped to visualize the two-dimensional distribution of myocardial ischemia with NADH fluorescence (NADH-F) in 22 dogs. NADH-F was developed at an MAoP of 40 mmHg or less and involved both the subendocardial half and the subepicardial half of the left ventricle [34 +/- 14 vs. 20 +/- 14% (P < 0.05) and 65 +/- 16 vs. 52 +/- 15% (not significant) of the cross-sectional area of the left ventricular slice at MAoP levels of 40 and 30 mmHg, respectively]. Magnified NADH-F photography demonstrated heterogeneously distributed microischemic lesions with a columnar shape (mode of short-axis length, 60-80 microns). NADH-F-guided microsamplings revealed higher NADH and lactate concentrations in a positive NADH-F area than those in a negative NADH-F area. The ratio of endocardial to epicardial blood flow was maintained at a relatively high level (1.07 +/- 0.07 and 0.88 +/- 0.07 at MAoP levels of 40 and 30 mmHg, respectively; n = 7 dogs), and the reactive hyperemia was preserved as well. In conclusion, myocardial ischemia in early hemorrhagic shock was characterized by minimal transmural heterogeneity and marked heterogeneity between contiguous small regions.

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2.03: Assessment of myocardial ischemia in areas of abnormal blood flow distribution with dobutamine stress and Multi-Pinhole (MP)-SPECT

Journal of Nuclear Cardiology ◽

10.1016/j.nuclcard.2008.06.061 ◽

2008 ◽

Vol 15 (4) ◽

pp. S2-S3

Author(s):

D KIRCH ◽

J KOSS ◽

S MODE ◽

P STEELE

Keyword(s):

Blood Flow ◽

Myocardial Ischemia ◽

Flow Distribution ◽

Dobutamine Stress ◽

Blood Flow Distribution

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Left ventricular cannulation for microsphere estimation of rabbit renal blood flow

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1980.238.5.h736 ◽

1980 ◽

Vol 238 (5) ◽

pp. H736-H739 ◽

Cited By ~ 1

Author(s):

J. Bhattacharya ◽

L. J. Beilin

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Renal Blood Flow ◽

Regional Blood Flow ◽

Flow Distribution ◽

Left Ventricular ◽

Blood Flow Distribution ◽

Per Se ◽

Conscious Animals ◽

Renal Blood Flow Distribution

When cannulation of the left ventricle and the left atrium were compared as methods for measuring for measuring renal blood flow distribution with radioactive microspheres in 9 conscious and 6 anesthetized rabbits, there were no differences between the two injection routes. Left ventricular cannulation per se did not affect cardiac output, nor the percentage of the cardiac output supplying the kidneys; but cardiac outputs estimated by thermodilution by injections via this route were up to 10% greater than those from left atrial injection. The advantages of left ventricular cannulation for experiments on regional blood flow distribution in conscious animals are discussed.

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FEASIBILITY TO CONTROL THE BLOOD FLOW DISTRIBUTION DURING LEFT VENTRICULAR ASSISTANCE

ASAIO Journal ◽

10.1097/00002480-200203000-00066 ◽

2002 ◽

Vol 48 (2) ◽

pp. 141

Author(s):

Shin-ichi Nitta ◽

Kouichi Tabayashi

Keyword(s):

Blood Flow ◽

Flow Distribution ◽

Left Ventricular ◽

Blood Flow Distribution ◽

Ventricular Assistance ◽

Left Ventricular Assistance

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Estimation of intramyocardial pressure and coronary blood flow distribution

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.255.3.h664 ◽

1988 ◽

Vol 255 (3) ◽

pp. H664-H672 ◽

Cited By ~ 3

Author(s):

Y. Sun ◽

H. Gewirtz

Keyword(s):

Blood Flow ◽

Coronary Blood Flow ◽

Coronary Circulation ◽

Regression Line ◽

Flow Distribution ◽

Left Ventricular Pressure ◽

Left Ventricular ◽

Blood Flow Distribution ◽

Intramyocardial Pressure ◽

D Model

To characterize the intramyocardial pressure (IMP) and coronary blood flow distribution in a stenosed coronary circulation, we compared four analog circuits for modeling coronary impedance. The resistor (R)-diode (D) model simulates vascular collapse, and the capacitor (C) simulates compliance effect. Identification of the best model and magnitudes of the endocardial and epicardial IMPs (IMPendo and IMPepi) was done retrospectively using data from studies in 28 anesthetized swine. Performance evaluation was based on comparison of model predicted vs. observed coronary distal pressure (DP) waveforms and endocardial-to-epicardial (endo-epi) flow ratios as determined by radiolabeled microspheres. The R-D-C model gave the best performance at IMPendo = 1.1 times left ventricular pressure (LVP), and IMPepi = 0.1.LVP + 15 mmHg; with good fit to DP (r = 0.98, slope of regression line = 1.0) and estimates of endo-epi flow ratio (r = 0.78, slope = 1.01, P less than 0.02, SEE = 0.21, n = 139). The R-D model gave comparable results even though capacitance was omitted. Although R-C and R models predicted distal coronary pressure well, they failed to predict endo-epi flow ratios (r less than 0.50). The R-D-C and R-D models were applied in seven prospective studies. Both models generated reasonable estimates of endo-epi flow distribution (r = 0.78, n = 50). Thus the R-D-C or R-D models of the stenosed coronary circulation can be used to provide reliable estimates of transmural blood flow distribution.

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