scholarly journals Effects of intravenous nesiritide on coronary vasomotor regulation and myocardial oxygen extraction

2003 ◽  
Vol 41 (6) ◽  
pp. 205 ◽  
Author(s):  
Andrew D. Michaels ◽  
Andrew Klein ◽  
Kanu Chatterjee
Keyword(s):  
Oxygen Extraction ◽  
Vasomotor Regulation ◽  
Myocardial Oxygen Extraction

Effects of levosimendan on coronary vasomotor regulation and myocardial oxygen extraction

2004 ◽  
Vol 10 (4) ◽  
pp. S91
Author(s):  
Andrew D. Michaels ◽  
Kalpesh T. Vakharia ◽  
Michael Kostal ◽  
Mark V. Jordan ◽  
Kanu Chatterjee
Keyword(s):  
Oxygen Extraction ◽  
Vasomotor Regulation ◽  
Myocardial Oxygen Extraction

Decrease in myocardial oxygen extraction with aortic constriction in the dog

1982 ◽  
Vol 242 (3) ◽  
pp. H310-H313
Author(s):  
D. Saito ◽  
S. Kusachi ◽  
O. Nishiyama ◽  
K. Yasuhara ◽  
S. Haraoka ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Vagal Stimulation ◽  
Aortic Pressure ◽  
Oxygen Extraction ◽  
Adrenergic Blockade ◽  
Descending Thoracic Aorta ◽  
Coronary Vasodilation ◽  
Aortic Constriction ◽  
Myocardial Oxygen Extraction

In the open-chest dog constriction of the descending thoracic aorta, which raises central aortic pressure by 30-80 mmHg, increases cardiac oxygen usage (MVO2) and coronary blood flow (CBF) but reduces heart rate and myocardial oxygen extraction [(A-V)O2]. Pacing tachycardia superimposed on aortic constriction further increases MVO2 and CBF but does not alter (A-V)O2. Atropine or vagotomy abolishes the effect of aortic constriction on (A-V)O2, whereas vagal stimulation in the presence of alpha- and beta-adrenergic blockade reduces (A-V)O2. L-propranolol and phenoxybenzamine fail to modify the effect of aortic constriction on (A-V)O2. These results indicate that aortic constriction reduces (A-V)O2 by eliciting parasympathetically-mediated coronary vasodilation.

Is Calcium a Coronary Vasoconstrictor In Vivo? 

1998 ◽  
Vol 88 (3) ◽  
pp. 735-743 ◽  
Author(s):  
George J. Crystal ◽  
Xiping Zhou ◽  
Ramez M. Salem
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Coronary Blood Flow ◽  
Myocardial Oxygen Consumption ◽  
Extraction Ratio ◽  
Oxygen Extraction ◽  
Oxygen Extraction Ratio ◽  
Myocardial Oxygen Extraction ◽  
Dose Dependent

Background Calcium produces constriction in isolated coronary vessels and in the coronary circulation of isolated hearts, but the importance of this mechanism in vivo remains controversial. Methods The left anterior descending coronary arteries of 20 anesthetized dogs whose chests had been opened were perfused at 80 mmHg. Myocardial segmental shortening was measured with ultrasonic crystals and coronary blood flow with a Doppler flow transducer. The coronary arteriovenous oxygen difference was determined and used to calculate myocardial oxygen consumption and the myocardial oxygen extraction ratio. The myocardial oxygen extraction ratio served as an index of effectiveness of metabolic vasodilation. Data were obtained during intracoronary infusions of CaCl2 (5, 10, and 15 mg/min) and compared with those during intracoronary infusions of dobutamine (2.5, 5.0, and 10.0 microg/min). Results CaCl2 caused dose-dependent increases in segmental shortening, accompanied by proportional increases in myocardial oxygen consumption. Although CaCl2 also increased coronary blood flow, these increases were less than proportional to those in myocardial oxygen consumption, and therefore the myocardial oxygen extraction ratio increased. Dobutamine caused dose-dependent increases in segmental shortening and myocardial oxygen consumption that were similar in magnitude to those caused by CaCl2. In contrast to CaCl2, however, the accompanying increases in coronary blood flow were proportional to the increases in myocardial oxygen consumption, with the result that the myocardial oxygen extraction ratio remained constant. Conclusions Calcium has a coronary vasoconstricting effect and a positive inotropic effect in vivo. This vasoconstricting effect impairs coupling of coronary blood flow to the augmented myocardial oxygen demand by metabolic vascular control mechanisms. Dobutamine is an inotropic agent with no apparent direct action on coronary resistance vessels in vivo.

scholarly journals 995-20 Effect of Hypoxia on Coronary Blood Flow and Myocardial Oxygen Extraction in Patients with Coronary Artery Disease

1995 ◽  
Vol 25 (2) ◽  
pp. 322A
Author(s):  
Achille Gaspardone ◽  
Patrizio Polisca ◽  
Filippo Crea ◽  
Fabrizio Tomai ◽  
Francesco Versaci ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Blood Flow ◽  
Coronary Artery ◽  
Coronary Blood Flow ◽  
Oxygen Extraction ◽  
Artery Disease ◽  
Myocardial Oxygen Extraction

The relationship between oxygen extraction and extravascular mean transit time in the canine heart

1977 ◽  
Vol 55 (3) ◽  
pp. 478-481 ◽  
Author(s):  
R. R. Mildenberger ◽  
A. L'Abbate ◽  
D. T. Zborowska-Sluis ◽  
G. A. Klassen
Keyword(s):  
Transit Time ◽  
Myocardial Oxygen Consumption ◽  
Mean Transit Time ◽  
Time Dependent ◽  
Oxygen Extraction ◽  
Canine Heart ◽  
Myocardial Oxygen Extraction ◽  
The Relationship ◽  
Mean Time ◽  
Critical Link

A significant relationship was observed between myocardial oxygen extraction and the extravascular mean time transit time. This relationship implies that oxygen extraction by the myocardium is a time-dependent process, and emphasizes the critical link between blood flow and myocardial oxygen consumption.

Myocardial oxygen extraction ratio is decreased during endotoxemia in pigs

1995 ◽  
Vol 79 (2) ◽  
pp. 479-486 ◽  
Author(s):  
M. J. Herbertson ◽  
H. A. Werner ◽  
J. A. Russell ◽  
K. Iversen ◽  
K. R. Walley
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Extraction Ratio ◽  
Oxygen Extraction ◽  
Ventricular Contractility ◽  
Oxygen Extraction Ratio ◽  
Extraction Capacity ◽  
Myocardial Oxygen Extraction ◽  
Increased Blood Flow

Why the myocardial oxygen extraction ratio (ERm) is decreased during septic shock in humans is unknown. Therefore, we calculated ERm in 15 anesthetized pigs by measuring arterial and coronary venous oxygen content. We measured myocardial lactate flux, myocardial contractility, and global myocardial blood flow and its distribution. After baseline measurements, animals received either saline (n = 6) or 50 micrograms/kg of endotoxin (n = 9). Measurements were repeated for 4 h. After endotoxin, ERm decreased from 67 +/- 12% at baseline to 36 +/- 10% (P < 0.01) at 1 h and 54 +/- 10% (P < 0.05) at 4 h, associated with an increased myocardial blood flow that was heterogeneous. Neither myocardial oxygen nor lactate consumption decreased in the endotoxin group, and changes in left ventricular contractility were not correlated with changes in ERm. We conclude that the decrease in ERm after endotoxin infusion is due to both increased blood flow and mismatching between myocardial oxygen delivery and demand. Impaired myocardial oxygen extraction capacity during sepsis did not cause global myocardial tissue hypoxia.

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