Adenosine release by the myocardium has been linked to a decrease in myocardial oxygen content and has been implicated in producing the concomitant increase in coronary flow. Epinephrine, norepinephrine, and histamine increase myocardial oxygen consumption and coronary flow. Nitroglycerin on the other hand, increases coronary flow but does not increase oxygen consumption. The purpose of the pre...

AVAILABLE data concerning coronary flow in intact human subjects have indicated that there is a strong tendency for the blood flow per unit weight of myocardium to fall in the usual range under a wide variety of circumstances and for the coronary vessels to be capable of adapting themselves to most situations sufficiently well to maintain usual coronary flow as long as myocardial metabolism is ...

The adenine nucleotide hypothesis postulates that the ATP released from red blood cells is broken down to ADP and AMP in coronary capillaries and that ATP, ADP, and AMP act on purinergic receptors on the surface of capillary endothelial cells. Purinergic receptor activation initiates a retrograde conducted vasodilator signal to the upstream arteriole that controls coronary blood flow in a negat...

The induction of spinal anesthesia resulted in hypotension and decreased coronary blood flow and myocardial oxygen consumption. At the same time the myocardial extraction coefficient of oxygen was not increased, indicating myocardial oxygenation to be adequate for the lower work load. This does not imply that local ischemia might not occur in the presence of coronary artery sclerosis. The coron...

The effect of smoking on the heart has been a controversial subject. The present studies were undertaken to investigate the effect of cigarette smoking on the coronary flow, myocardial usage of oxygen and myocardial extraction of glucose, pyruvate, lactate, and ketones. Catheterization of the coronary sinus revealed that cigarette smoking in patients without heart disease results in a significa...

Objective—Introduction and measurement of human myocardial oxygen supply:demand ratio as a reference for quantification of coronary microvascular vasodilating drug effects in clinical studies. Myocardial oxygen consumption is the major determinant of coronary blood flow; therefore, the true vasodilating properties of coronary vasodilating drugs that may have an effect on oxygen consumption cann...

Decreased cardiac output, coronary blood flow, and systemic oxygen transport in polycythemia are attributed to increased blood viscosity and regarded as potentially harmful. We studied the effects of isovolemic polycythemia on these variables as well as on myocardial oxygen consumption and regional myocardial blood flow in 31 anesthetized dogs, seven with cannulated left main coronary arteries....

OBJECTIVE Introduction and measurement of human myocardial oxygen supply:demand ratio as a reference for quantification of coronary microvascular vasodilating drug effects in clinical studies. Myocardial oxygen consumption is the major determinant of coronary blood flow; therefore, the true vasodilating properties of coronary vasodilating drugs that may have an effect on oxygen consumption cann...