Relation between oxygen consumption and pressure-volume area of in situ dog heart

1987 ◽  
Vol 253 (1) ◽  
pp. H31-H40 ◽  
Author(s):  
T. Nozawa ◽  
Y. Yasumura ◽  
S. Futaki ◽  
N. Tanaka ◽  
Y. Igarashi ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Left Ventricle ◽  
Systolic Pressure ◽  
Ascending Aorta ◽  
Aortic Occlusion ◽  
O2 Consumption ◽  
Loading Conditions ◽  
Contractile State ◽  
Dog Heart

We studied the relation between O2 consumption (VO2) and the systolic pressure-volume area (PVA) in the left ventricle of open-chest dogs. PVA and the slope (Emax) of the end-systolic pressure-volume line were determined by an abrupt occlusion of the ascending aorta. VO2 linearly correlated with PVA in control contractile state, where Emax was 15.8 +/- 4.4 (SD) mmHg/ml with intact reflexes and 11.5 +/- 1.2 mmHg/ml with blocked reflexes. Emax and the VO2 axis intercept of the VO2-PVA line were greater in the in situ heart than in the excised cross-circulated dog heart in our previous study. Enhancement of contractile state by dobutamine increased Emax by 60–80% and shifted the VO2-PVA line upward, increasing the VO2 axis intercept by 38% with intact reflexes and by 79% with blocked reflexes. The slope had a tendency to increase with dobutamine, but the increase was statistically insignificant. We conclude that PVA and Emax obtained by the aortic-occlusion method can account for changes in VO2 with changes in loading conditions and contractility in an in situ dog heart.

Assessment of slope of end-systolic pressure-volume line of in situ dog heart

1986 ◽  
Vol 250 (4) ◽  
pp. H685-H692 ◽  
Author(s):  
Y. Igarashi ◽  
H. Suga
Keyword(s):  
Systolic Pressure ◽  
Electromagnetic Flowmeter ◽  
Left Ventricular ◽  
Aortic Occlusion ◽  
Atrial Pacing ◽  
Ventricular Contractility ◽  
Dog Heart ◽  
End Diastolic Volume ◽  
Isovolumic Contraction

The purpose of this study was to establish a new method of assessment of the slope (Emax) of the end-systolic pressure-volume line (ESPVL) of the in situ heart. In anesthetized open-chest dogs, an isovolumic contraction was produced by an aortic occlusion after steady-state ejecting contractions in the left ventricle. We plotted ventricular pressure measured with a catheter-tip manometer against time integral of aortic flow measured with an electromagnetic flowmeter of the last ejecting and the first isovolumic contraction, assuming the same end-diastolic volume. ESPVL was drawn from the peak isovolumic pressure-volume point tangential to the left upper corner of the +/- 3.0 (SE) mmHg/ml (n = 9 dogs) in control run and was increased by 59 +/- 19% under isoproterenol and decreased by 47 +/- 9% after propranolol. Emax was little changed by atrial pacing. We conclude that Emax by this aortic occlusion method is useful for assessment of left ventricular contractility of the in situ dog heart.

Heart rate-independent energetics and systolic pressure-volume area in dog heart

1983 ◽  
Vol 244 (2) ◽  
pp. H206-H214 ◽  
Author(s):  
H. Suga ◽  
R. Hisano ◽  
S. Hirata ◽  
T. Hayashi ◽  
O. Yamada ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Left Ventricle ◽  
Mechanical Energy ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Canine Heart ◽  
Heart Rates ◽  
Dog Heart ◽  
Total Mechanical Energy

Left ventricular (LV) systolic pressure-volume area (PVA), a new measure of total mechanical energy for the contraction, linearly correlates with its oxygen consumption per beat (VO2) regardless of contraction mode in a canine heart with stable chronotropism and inotropism. PVA is the area in the pressure-volume (PV) diagram circumscribed by the end-systolic and end-diastolic PV relation curves and the systolic segment of the PV loop and has dimensions of energy. We investigated whether primary changes in heart rate would affect the VO2-PVA relation. In the excised cross-circulated canine heart with left ventricular load controlled with a servo pump, we changed heart rate by pacing to compare the VO2-PVA relations at low [124 +/- 17 (SD) min-1] and high (193 +/- 23) heart rates. In 15 left ventricles, VO2 (ml O2 X beat-1 X 100 g LV-1) was (1.75 +/- 0.57) X 10(-5) PVA (mmHg X ml X beat-1 X 100 g LV-1) + 0.031 +/- 0.011 (ml O2 X beat-1 X 100 g LV-1). The VO2-PVA relation was virtually independent of heart rate in individual hearts. We conclude that the load-independent VO2-PVA relationship is not affected by chronotropism in a given canine left ventricle.

Oxygen consumption and pressure-volume area of abnormal contractions in canine heart

1984 ◽  
Vol 246 (2) ◽  
pp. H154-H160 ◽  
Author(s):  
H. Suga ◽  
O. Yamada ◽  
Y. Goto ◽  
Y. Igarashi
Keyword(s):  
Oxygen Consumption ◽  
Linear Regression ◽  
Left Ventricle ◽  
Correlation Coefficient ◽  
Regression Line ◽  
Systolic Pressure ◽  
Canine Heart ◽  
Regression Analyses ◽  
Contractile State ◽  
Consumption Rates

Oxygen consumption rates (VO2) of isovolumic and normally ejecting contractions are closely correlated with their systolic pressure-volume areas (PVA) in a stable canine left ventricle. PVA is the area in the pressure-volume (PV) diagram that is circumscribed by the end-systolic and end-diastolic PV relation curves and the systolic segment of the PV loop trajectory. We studied whether VO2s of abnormally loaded ejecting contractions were similarly correlated with their PVAs. Various abnormally ejecting contractions were produced in the left ventricle of the cross-circulated canine heart. VO2 and PVA data of the various abnormal contractions and the isovolumic and normally ejecting contractions were pooled together, to which the correlation and regression analyses were applied. They could be fitted by a linear regression analyses were applied. They could be fitted by a linear regression line with a high correlation coefficient and a slight scatter in each heart. We therefore conclude that PVA is the primary correlate of VO2, not only in the isovolumic and normally ejecting contractions but also in various abnormally loaded contractions in a given canine left ventricle with a stable contractile state.

Rhythm effects on contractility of the beating isovolumic left ventricle

1960 ◽  
Vol 199 (6) ◽  
pp. 1115-1120 ◽  
Author(s):  
B. Lendrum ◽  
H. Feinberg ◽  
E. Boyd ◽  
L. N. Katz
Keyword(s):  
Heart Rate ◽  
Left Ventricle ◽  
Systolic Pressure ◽  
Ventricular Volume ◽  
Contractile Force ◽  
Postextrasystolic Potentiation ◽  
Pressure Development ◽  
Induced Changes ◽  
Electrical Alternans

Variation in contractile force of the isovolumic contracting left ventricle of the dog was studied in open-chested in situ hearts. The electrocardiogram and intraventricular pressures were recorded at various heart volumes. Spontaneous changes in heart rate and rhythm occurred at all volumes. Isovolumic systolic pressure development (contractile force) varied with rate and rhythm. Contractile force increased with heart rate (treppe) regardless of pacemaker origin. When a premature beat was followed by a compensatory pause, the premature beat showed a decrease and the next beat an increase in contractile force (postextrasystolic potentiation). The magnitude of the changes varied directly with the prematurity of the beat. Mechanical alternans was observed with electrical alternans, despite the absence of significant volume change. Rate-induced changes, postextrasystolic potentiation and mechanical alternans were additive when they occurred simultaneously. For practical purposes, ventricular volume (filling), hence muscle fiber length, remained constant during these rate and rhythm change, therefore could not affect the strength of contraction. Contractile force changes directly attributable to rate and rhythm changes do, therefore, occur in the intact mammalian heart.

scholarly journals Cardiac cooling increases Emax without affecting relation between O2 consumption and systolic pressure-volume area in dog left ventricle.

1988 ◽  
Vol 63 (1) ◽  
pp. 61-71 ◽  
Author(s):  
H Suga ◽  
Y Goto ◽  
Y Igarashi ◽  
Y Yasumura ◽  
T Nozawa ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Systolic Pressure ◽  
O2 Consumption

Similar normalized Emax and O2 consumption-pressure-volume area relation in rabbit and dog

1988 ◽  
Vol 255 (2) ◽  
pp. H366-H374 ◽  
Author(s):  
Y. Goto ◽  
B. K. Slinker ◽  
M. M. LeWinter
Keyword(s):  
Left Ventricle ◽  
Systolic Pressure ◽  
Energy Conversion Efficiency ◽  
Left Ventricular ◽  
Energy Transduction ◽  
Base Line ◽  
Contractile State ◽  
Primary Determinant ◽  
Heart Size ◽  
Volume Relation

The end-systolic pressure-volume relation (ESPVR), a measure of ventricular contractile state, and systolic pressure-volume area (PVA), a primary determinant of cardiac oxygen consumption per beat (VO2), have been derived from the pressure-volume diagram of the cross-circulated dog left ventricle. The slope of the PVA-VO2 relation represents the efficiency of chemomechanical energy transduction of the contractile machinery. To see whether these relationships were similar in other animals, we studied the isovolumic ESPVR and the VO2-PVA relation in nine excised, cross-circulated rabbit left ventricles. The base-line ESPVR was linear (r = 0.94-0.99) with the slope (Emax) and volume-axis intercept (V0) equal to 83.4 +/- 18.3 mmHg/ml and 0.43 +/- 0.17 ml, respectively. When normalized for left ventricular weight, Emax (4.1 +/- 1.1 mmHg.ml-1.100 g) and V0 (8.9 +/- 3.7 ml/100 g) were similar to values reported for the dog left ventricle. The correlation between PVA and VO2 was linear (r = 0.93-1.00), and the slope (1.90 X 10(-5) +/- 0.44 X 10(-5) ml O2.mmHg-1.ml-1) and VO2-axis intercept (0.040 +/- 0.009 ml O2.beat-1.100 g-1) were similar to values found in the dog left ventricle. Hence, despite the greatly different heart size, the base-line contractile state and chemomechanical energy conversion efficiency of the excised, cross-circulated rabbit left ventricle are similar to those of the dog left ventricle.

ESPVR of in situ rat left ventricle shows contractility-dependent curvilinearity

1998 ◽  
Vol 274 (5) ◽  
pp. H1429-H1434 ◽  
Author(s):  
Takayuki Sato ◽  
Toshiaki Shishido ◽  
Toru Kawada ◽  
Hiroshi Miyano ◽  
Hiroshi Miyashita ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Linear Regression Analysis ◽  
Systolic Pressure ◽  
Quadratic Equation ◽  
Left Ventricular ◽  
Conductance Catheter ◽  
Electromagnetic Flowmetry ◽  
Significant Difference ◽  
Pressure Volume Relationship

We developed a miniaturized conductance catheter for in situ rat left ventricular (LV) volumetry. After the validation study of the conductance volumetry in 11 rats, we characterized the end-systolic pressure-volume relationship (ESPVR) in 24 sinoaortic-denervated, vagotomized and urethan-anesthetized rats. Stroke volume (SV) measured with the conductance catheter correlated closely with that measured by electromagnetic flowmetry ( r > 0.95). No significant difference was found between the in situ LV end-diastolic volumes measured by conductance volumetry and postmortem morphometry; a linear regression analysis indicated that the correlation coefficient was 0.934, that the slope was not significantly different from 1, and that the intercept was not significantly different from 0. During cardiac sympathotonic conditions, the ESPVR was curvilinear. The estimated slope of ESPVR (end-systolic elastance, E es) by quadratic curve fitting at end-systolic pressure of 100 mmHg was 2,647 ± 846 mmHg/ml. Bilateral cervical and stellate ganglionectomy depressed contractility and made the ESPVR linear; a quadratic equation did not improve the fit. E es was 946 ± 55 mmHg/ml with the volume-axis ( V 0) intercept of 0.076 ± 0.007 ml. Administration of propranolol (1 mg/kg) further reduced E es (573 ± 61 mmHg/ml, P < 0.001) and increased V 0 slightly (0.091 ± 0.011 ml). We conclude that the conductance catheter method is useful for the assessment of the ESPVR of the in situ rat left ventricle and that the ESPVR displays contractility-dependent curvilinearity.

Relation between oxygen consumption and pressure-volume area of in situ dog heart

1987 ◽  
Vol 253 (1) ◽  
pp. 1-1 ◽  
Author(s):  
T. Nozawa ◽  
Y. Yasumura ◽  
S. Futaki ◽  
N. Tanaka ◽  
Y. Igarashi ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Standard Deviation ◽  
Degrees Of Freedom ◽  
Regression Line ◽  
Computer Software ◽  
Confidence Limits ◽  
Sampled Data ◽  
Dog Heart ◽  
Data Points

Page H31: T. Nozawa, Y. Yasumura, S. Futaki, N. Tanaka, Y. Igarashi, Y. Goto, and H. Suga. “Relation between oxygen consumption and pressure-volume area of in situ dog heart.” Page H37: Fig. 6: Although the last sentence of the legend states “Solid lines are linear regression lines, and inner and outer pairs of dashed curves around them are 95% confidence limits of regression lines and data points, respectively,” these dashed lines show one standard deviation of both the slope of the regression line and the sampled data from the regression line. The authors forgot to multiply these standard deviation values by t value (2.069 for degrees of freedom = 23) for P le 0.05 in the computer software to obtain the 95% confidence limits. The other statistical results in Fig. 6 are correct.

Frequency-force relationships of mammalian ventricular muscle in vivo and in vitro

1976 ◽  
Vol 230 (3) ◽  
pp. 631-636 ◽  
Author(s):  
ML Kahn ◽  
F Kavaler ◽  
VJ Fisher
Keyword(s):  
Heart Rate ◽  
Left Ventricle ◽  
Room Temperature ◽  
Physiological Role ◽  
Ventricular Muscle ◽  
Contractile State ◽  
Force Relationship

The change in contractility with increasing heart rate was studied in the left ventricle of dogs and in isolated trabeculae carneae of cats. For some of the studies in situ a transient isovolumic state was created by aortic occlusion. At physiological temperatures the frequency-force relationship is flatter than at room temperature and at the same temperature it is flatter in vivo than in vitro. The frequency-(dF/dt)max relationship is steeper than the frequency-force relationship at both temperatures in vivo and in vitro. The frequency-(dF/dt)max relationship is steeper in vitro than it is in situ, although the discrepancy is less marked than in the case of the frequency-force relationship. It is concluded that "staircase" plays less of a physiological role in adjustment of contractile state in situ than might be inferred from studies of isolated tissue.

Myoglobin function in the isolated fluorocarbon-perfused dog heart

1978 ◽  
Vol 234 (5) ◽  
pp. H567-H572 ◽  
Author(s):  
R. P. Cole ◽  
B. A. Wittenberg ◽  
P. R. Caldwell
Keyword(s):  
Oxygen Consumption ◽  
Left Ventricle ◽  
Mechanical Performance ◽  
Left Ventricular Pressure ◽  
Dry Weight ◽  
Left Ventricular ◽  
Facilitated Diffusion ◽  
Dog Heart ◽  
Before And After ◽  
Ringer’S Lactate

An isolated dog heart preparation perfused with hemoglobin-free fluorocarbon suspension has been developed to study the role of myoglobin in myocardial function. The coronary vasculature was perfused at constant flow, with oxygen consumption determined from arteriovenous PO2 differences. Muscle function was assessed by measurement of pressures generated in a latex balloon placed in the left ventricle. The perfusate consisted of 20% perfluorotributylamine and 80% Ringer's lactate with 16 mM glucose. Steady-state oxygen consumption decreased from 0.30 to 0.11 ml/min per gram dry weight left ventricle, as perfusate PO2 decreased from 690 to 150 mmHg. Left ventricular pressure generation and oxygen consumption were determined before and after addition of 8 mM sodium nitrite, which changed functional ferrous myoglobin to high-spin ferric myoglobin. Over the range of perfusate PO2 studied, nitrite addition did not alter mechanical performance or myocardial oxygen consumption. These data suggest that those conditions necessary for substantial myoglobin-facilitated diffusion of oxygen in the myocardium are not present in the isolated fluorocarbon-perfused dog heart.

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