Mechanical determinants of myocardial oxygen consumption with special reference to external work and efficiency

Levosimendan is an inotropic and vasodilator drug, which is known to improve cardiac function in animal models of right ventricular (RV) failure. The effects of levosimendan on oxygen consumption and myocardial efficiency in the failing RV is unknown. We investigated the effects of levosimendan on RV function, myocardial oxygen consumption, myocardial external efficiency (MEE), and myocardial metabolism in rats with RV hypertrophy and failure. RV hypertrophy and failure were induced by pulmonary trunk banding in rats. Rats were randomized to seven weeks of treatment with vehicle (n = 16) or levosimendan (3 mg/kg/day) (n = 13). Control animals without pulmonary banding received vehicle treatment (n = 11). RV MEE and RV metabolism were evaluated by echocardiography, 11C-acetate positron emission tomography (PET), 18F-FDG PET, and invasive pressure measurements. We found that levosimendan improved RV MEE (26 ± 3 vs. 14 ± 1%, P < 0.01) by increasing RV external work (0.62 ± 0.06 vs. 0.30 ± 0.03 mmHgċmL, P < 0.001) without affecting RV myocardial oxygen consumption ( P = 0.64). The improvement in RV MEE was not associated with a change in RV myocardial glucose uptake (1.3 ± 0.1 vs. 1.0 ± 0.1 µmol/g/min, P = 0.44). In conclusion, in the hypertrophic and failing RV of the rat, levosimendan improves RV function without increasing myocardial oxygen consumption leading to improved MEE. The improvement in RV MEE was not associated with a change in myocardial glucose uptake. This study emphasizes the potential therapeutic value of chronic levosimendan treatment RV failure. It extends previous observations on the effect profile of levosimendan and motivates clinical testing of levosimendan in RV failure.

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Cardiovascular effects of high doses of thiamine (Vit. B1) in the dog with special reference to myocardial oxygen consumption

Basic Research in Cardiology ◽

10.1007/bf01927871 ◽

1976 ◽

Vol 71 (2) ◽

pp. 192-198

Author(s):

E. Freye

Keyword(s):

Oxygen Consumption ◽

Special Reference ◽

Myocardial Oxygen Consumption ◽

Cardiovascular Effects ◽

High Doses

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The Effect of Pacing Mode on External Work and Myocardial Oxygen Consumption

Cardiac Pacing ◽

10.1007/978-3-642-72367-4_28 ◽

1983 ◽

pp. 181-186 ◽

Cited By ~ 2

Author(s):

Yukihiro Koretsune ◽

Kazuhisa Kodama ◽

Shinsuke Nanto ◽

Kiyomu Ishikawa ◽

Koichi Taniura ◽

...

Keyword(s):

Oxygen Consumption ◽

Myocardial Oxygen Consumption ◽

External Work ◽

Pacing Mode

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Myocardial Oxygen Consumption During Dobutamine and Exercise Stress: Is it Equivalent?

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(97)84825-5 ◽

1998 ◽

Vol 31 (2) ◽

pp. 257A

Author(s):

R Parmar

Keyword(s):

Oxygen Consumption ◽

Myocardial Oxygen Consumption ◽

Exercise Stress

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Clinical and Experimental Analysis of 201Thallium Uptake of the Heart

Nuklearmedizin ◽

10.1055/s-0037-1620682 ◽

1978 ◽

Vol 17 (04) ◽

pp. 142-148

Author(s):

U. Büll ◽

S. Bürger ◽

B. E. Strauer

Keyword(s):

Oxygen Consumption ◽

Left Ventricle ◽

Muscle Mass ◽

Myocardial Oxygen Consumption ◽

Animal Experiments ◽

Left Ventricular ◽

Left Ventricular Wall ◽

Ventricular Wall ◽

Flow Measurements ◽

Myocardial Flow

Studies were carried out in order to determine the factors influencing myocardial 201T1 uptake. A total of 158 patients was examined with regard to both 201T1 uptake and the assessment of left ventricular and coronary function (e. g. quantitative ventriculography, coronary arteriography, coronary blood flow measurements). Moreover, 42 animal experiments (closed chest cat) were performed. The results demonstrate that:1) 201T1 uptake in the normal and hypertrophied human heart is linearly correlated with the muscle mass of the left ventricle (LVMM);2) 201T1 uptake is enhanced in the inner (subendocardial) layer and is decreased in the outer (subepicardial) layer of the left ventricular wall. The 201T1 uptake of the right ventricle is 40% lower in comparison to the left ventricle;3) the basic correlation between 201T1 uptake and LVMM is influenced by alterations of both myocardial flow and myocardial oxygen consumption; and4) inotropic interventions (isoproterenol, calcium, norepinephrine) as well as coronary dilatation (dipyridamole) may considerably augment 201T1 uptake in accordance with changes in myocardial oxygen consumption and/or myocardial flow.It is concluded that myocardial 201T1 uptake is determined by multiple factors. The major determinants have been shown to include (i) muscle mass, (ii) myocardial flow and (iii) myocardial oxygen consumption. The clinical data obtained from patient groups with normal ventricular function, with coronary artery disease, with left ventricular wall motion abnormalities and with different degree of left ventricular hypertrophy are correlated with quantitated myocardial 201T1 uptake.

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