Myoglobin oxygenation remains constant during the cardiac cycle

1983 ◽  
Vol 245 (2) ◽  
pp. H237-H243 ◽  
Author(s):  
N. Makino ◽  
H. Kanaide ◽  
R. Yoshimura ◽  
M. Nakamura
Keyword(s):  
Steady State ◽  
Oxygen Saturation ◽  
Fiber Optics ◽  
Wall Thickness ◽  
Cardiac Cycle ◽  
Left Ventricular ◽  
Isolated Rat Heart ◽  
Left Ventricular Free Wall ◽  
Absorbance Change ◽  
Aerobic And Anaerobic

Oxygen saturation of myoglobin (Mb) during the cardiac cycle was recorded spectrophotometrically by incorporating fiber optics in the isolated rat heart perfused using the Langendorff procedure. Oxygen saturation of Mb was continuously measured from absorbancy increments at 581-592 nm of transmitted light through the left ventricular free wall. In addition, quantification in the Mb oxygen saturation induced by the change of wall thickness during cardiac cycle was assessed from the absorbance change at 568-592 nm, namely, dual wavelengths of two isosbestic points. The results show that to obtain actual Mb oxygen saturation the absorbance change induced by the change in the wall thickness has to be subtracted from the absorbance change of 581-592 nm and that the Mb oxygen saturation in a steady state determines the amount of subtraction. On the basis of these procedures, it was found that the myocardial Mb oxygen saturation and hence myocardial oxygen tension during pulsation in aerobic and anaerobic steady state did not vary during the cardiac cycle.

Assessment of Myocardial Viability in Persistent Defects on Thallium-201 SPECT after Reinjection Using Gradient-Echo MRI

1996 ◽  
Vol 35 (05) ◽  
pp. 146-152 ◽  
Author(s):  
A. Kögler ◽  
H.-A. Schmitt ◽  
D. Emrich ◽  
H. Kreuzer ◽  
D. L. Munz ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Myocardial Viability ◽  
Cardiac Cycle ◽  
Single Photon ◽  
Contractile Function ◽  
Left Ventricular ◽  
Wall Thickening ◽  
Gradient Echo ◽  
Systolic Wall Thickening

SummaryThis prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (± SD) was 11.5 ± 2.7 mm and 5.8 ± 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 ± 3.4 mm and 3.7 ± 3.1 mm in 31 with reversible lesions, 11.3 ± 2.8 mm and 3.3 ± 1.9 mm in 10 with mild persistent defects, 9.2 ± 2.9 mm and 3.2 ±2.2 mm in 15 with moderate persistent defects, 5.8 ± 1.7 mm and 1.3 ± 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p <0.0005) and systolic wall thickening (p <0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.

scholarly journals Uncertainty quantification and sensitivity analysis of left ventricular function during the full cardiac cycle

2020 ◽  
Vol 378 (2173) ◽  
pp. 20190381 ◽  
Author(s):  
J. O. Campos ◽  
J. Sundnes ◽  
R. W. dos Santos ◽  
B. M. Rocha
Keyword(s):  
Uncertainty Quantification ◽  
Wall Thickness ◽  
Cardiac Cycle ◽  
Fibre Orientation ◽  
Left Ventricular ◽  
Sensitivity Analyses ◽  
Patient Specific ◽  
Model Parameters ◽  
Fibre Direction ◽  
Active Stress

Patient-specific computer simulations can be a powerful tool in clinical applications, helping in diagnostics and the development of new treatments. However, its practical use depends on the reliability of the models. The construction of cardiac simulations involves several steps with inherent uncertainties, including model parameters, the generation of personalized geometry and fibre orientation assignment, which are semi-manual processes subject to errors. Thus, it is important to quantify how these uncertainties impact model predictions. The present work performs uncertainty quantification and sensitivity analyses to assess the variability in important quantities of interest (QoI). Clinical quantities are analysed in terms of overall variability and to identify which parameters are the major contributors. The analyses are performed for simulations of the left ventricle function during the entire cardiac cycle. Uncertainties are incorporated in several model parameters, including regional wall thickness, fibre orientation, passive material parameters, active stress and the circulatory model. The results show that the QoI are very sensitive to active stress, wall thickness and fibre direction, where ejection fraction and ventricular torsion are the most impacted outputs. Thus, to improve the precision of models of cardiac mechanics, new methods should be considered to decrease uncertainties associated with geometrical reconstruction, estimation of active stress and of fibre orientation. This article is part of the theme issue ‘Uncertainty quantification in cardiac and cardiovascular modelling and simulation’.

Regional myocardial function and metabolism during acute coronary artery occlusion

1982 ◽  
Vol 242 (6) ◽  
pp. H980-H989 ◽  
Author(s):  
H. Kanaide ◽  
R. Yoshimura ◽  
N. Makino ◽  
M. Nakamura
Keyword(s):  
Coronary Artery ◽  
Oxygen Saturation ◽  
Fiber Optics ◽  
Myocardial Function ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Isolated Rat Heart ◽  
Wall Thickening ◽  
Regional Ischemia ◽  
Systolic Wall Thickening

Regional changes in myocardial function and oxidative metabolism during acute coronary artery occlusion were recorded spectrophotometrically by incorporating fiber optics in the isolated rat heart perfused by Langendorff's procedure. Oxygen saturation of myoglobin, reduction of cytochrome aa3, and the dynamic wall thickness of the left ventricle were continuously and concurrently measured from absorbancy increments at 581-592 nm, 605-630 nm, and 568-592 nm, respectively. In contrast to a gradual decrease in the extent of systolic wall thickening in anoxia, observed decreases in both the extent and the duration of systolic wall thickening and the appearance of a late systolic bulge occurred within 5 s after the onset of regional ischemia. After 10 s of both anoxia and regional ischemia, oxygen saturation of myoglobin decreased by 50%, but fluorescence of nicotinamide adenine dinucleotide remained at aerobic level which indicated that mitochondrial oxidative energy production might still be maintained. Thus early and pronounced dysfunction of the ischemic region appeared to precede a substantial loss of ATP production.

scholarly journals Dynamic Changes in Left Ventricular Free Wall Thickness in the Human Heart

Circulation ◽  
1969 ◽  
Vol 39 (4) ◽  
pp. 455-464 ◽  
Author(s):  
LESLIE M. EBER ◽  
HARVEY M. GREENBERG ◽  
JOHN M. COOKE ◽  
RICHARD GORLIN
Keyword(s):  
Wall Thickness ◽  
Human Heart ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Free Wall ◽  
Left Ventricular Free Wall ◽  
Dynamic Changes

Influence of alterations in heart rate on left ventricular echocardiographic measurements in healthy cats

2016 ◽  
Vol 19 (8) ◽  
pp. 841-845 ◽  
Author(s):  
Keisuke Sugimoto ◽  
Yoko Fujii ◽  
Yuto Ogura ◽  
Hiroshi Sunahara ◽  
Takuma Aoki
Keyword(s):  
Heart Rate ◽  
Wall Thickness ◽  
Interventricular Septum ◽  
Left Ventricular ◽  
Right Atrial ◽  
Atrial Pacing ◽  
Free Wall ◽  
Left Ventricular Free Wall ◽  
Linear Fashion ◽  
Significant Relationships

Objectives The purpose of this study was to evaluate the effect of sudden alterations in heart rate (HR) on left ventricular (LV) wall thickness and dimensions determined by echocardiography in healthy cats. Methods Six experimental cats were used. All cats were anaesthetised and HR was controlled with right atrial pacing. The interventricular septum and left ventricular free wall thickness at end diastole (IVSd and LVFWd, respectively), left ventricular end-diastolic and end-systolic diameter (LVIDd and LVIDs, respectively) and shortening fraction (FS) of each cat were assessed using echocardiography at pacing rates of 120, 130, 140, 150, 160, 170 and 180 ppm. Results There were significant relationships between HR and IVSd, LVFWd, LVIDd, LVIDs and FS. As the HR increased, LV wall thickness increased and chamber dimensions got smaller in a linear fashion. The maximum and minimum differences in wall thickness between 120 ppm and 180 ppm were 2.0 mm and 0.7 mm in single measurements, respectively. Conclusions and relevance LV wall thickness and dimensions were significantly influenced by alterations in HR.

Porous medium finite element model of the beating left ventricle

1992 ◽  
Vol 262 (4) ◽  
pp. H1256-H1267 ◽  
Author(s):  
J. M. Huyghe ◽  
T. Arts ◽  
D. H. van Campen ◽  
R. S. Reneman
Keyword(s):  
Left Ventricle ◽  
Wall Thickness ◽  
Cardiac Cycle ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Fiber Direction ◽  
Intraventricular Pressure ◽  
Angle Distribution ◽  
Fiber Angle ◽  
Intramyocardial Pressure

The axisymmetric model described represents myocardial tissue as a spongy anisotropic viscoelastic material. It includes torsion around the axis of symmetry of the ventricle, transmural variation of fiber angle, and redistribution of intracoronary blood in the myocardial wall. In simulations, end-systolic principal strains were equal to 0.45, -0.01, and -0.24 at two-thirds of the wall thickness from the epicardium and 0.26, 0.00, and -0.19 at one-third of the wall thickness from the epicardium. The direction of maximal shortening varied by less than 30 degrees from epicardium to endocardium, whereas fiber direction varied by greater than 100 degrees from epicardium to endocardium. During a normal cardiac cycle peak, equatorial intramyocardial pressure differed by less than 5% from peak intraventricular pressure. When redistribution of intracoronary blood in the ventricular wall was suppressed, peak equatorial intramyocardial pressure was found to exceed peak intraventricular pressure by greater than 30%. Simulated contraction of an unloaded left ventricle (left ventricular pressure = 0 kPa) produced similar magnitude for systolic intramyocardial pressures as the normal cardiac cycle. Transmural systolic fiber stress distribution was very sensitive to the chosen transmural fiber angle distribution.

Rapid-freezing transmural cardiac biopsy drill

1981 ◽  
Vol 240 (1) ◽  
pp. H126-H132 ◽  
Author(s):  
J. R. Allard ◽  
R. L. Conhaim ◽  
G. J. Vlahakes ◽  
M. J. O'Neill ◽  
J. I. Hoffman
Keyword(s):  
Stainless Steel ◽  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Cardiac Cycle ◽  
Left Ventricular ◽  
Rapid Freezing ◽  
Free Wall ◽  
Left Ventricular Free Wall ◽  
Biopsy Site ◽  
Air Turbine

We have built a transmural cardiac biopsy drill that uses an air turbine (10,000 rpm) to turn a stainless steel bore of either 2.0 or 4.5 mm diam. Vacuum draws the cut biopsies through the drill into isopentane chilled to -150 degrees C with liquid nitrogen. The steel bores cut through the beating canine left ventricular free wall in 0.14 +/- 0.04 (SD) permitting sampling in discrete portions of the cardiac cycle. Small and large biopsies traverse the drill in 0.48 +/- 0.19 and 0.15 +/- 0.04 s, respectively. Large biopsies freeze in 1.46 +/- 0.73 s, whereas small biopsies are calculated to freeze in 0.28 s. Average biopsy weights are 34 +/- 14 and 180 +/- 71 mg. Left ventricular myocardial blood flow measured with radionuclide-labeled microspheres showed that muscle plugs sutured into wound sites of 4.5-mm-diam biopsies cause a 30% reduction in myocardial blood flow within 0.5 cm of the biopsy site. Light microscopy shows normal cardiac muscle with little damage from drill rotation.

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