Elucidation of the mechanism by which coronary flow is regulated has been attempted. Substances with coronary vasodilator or vasoconstrictor properties as well as those with inotropic or chronotropic effects on isolated frog hearts were sought in the coronary sinus blood of dogs. Blood draining normal, hypoxic or "overperfused" hearts was oxygenated in a dog lung or on a screen and perfused at ...

The effects on coronary dynamics of propranolol and atenolol were studied in 12 patients undergoing cardiac catheterisation for suspected coronary artery disease. Myocardial blood flow was measured using the coronary sinus continuous thermodilution technique. Data were obtained immediately after drug administration and during rapid atrial pacing. The immediate effects were similar for both drug...

Background. Platelet aggregation is believed to contribute to the precipitation of acute ischemic syndromes. Because physical activity has been proposed as one possible trigger in converting a patient with chronic coronary artery disease to one with an acute ischemic syndrome, we examined the hypothesis that platelets become activated when coronary blood flow velocities (and thereby shear stres...

Clinical and angiographic features of 31 patients with anomalous coronpary artery origin are reviewed. Of 17 aberrant circumflex arteries from the right sinus of Valsalva or artery, each was retro-aortic, six atherosclerotic, and seven irrigated a small area of myocardium. Of seven anomalous right coronary arteries from the left sinus of Valsalva or artery, each was ante-aortic and two atherosc...

A 61-year-old man was admitted to the hospital because of orthopnea and was diagnosed with heart failure with a continuous heart murmur. A transthoracic echocardiogram revealed turbulent flow from the right coronary sinus of Valsalva to the right atrium throughout the cardiac cycle. Aortography confirmed the presence of a shunt jet from the right coronary sinus of Valsalva to the right atrium. ...

Intracoronary administration of acetylcholine or efferent vagal stimulation causes coronary vasodilation in dogs. However, in baboons it has been reported that intracoronary acetylcholine results in a fall in coronary blood flow and that stimulation of the vagi is without effect. The dose response of intracoronary acetylcholine and the effect of efferent vagal stimulation on the coronary circul...

Effects of H1-receptor stimulation on coronary arterial diameter and coronary hemodynamics were examined in 11 patients with angiographically normal coronary arteries and without variant angina or resting angina. Selective H1-receptor stimulation was achieved by infusing histamine into the left coronary artery at a rate of 2.0 1£g/min for 5 minutes after pretreatment with cimetidine (25 mg/kg)....

Efferent vagal stimulation in the anesthetized dog with constant ventricular rate caused either no change in coronary sinus outflow and cardiac work, or a decrease in coronary sinus outflow associated with a greater decrease in cardiac work. When the decreases were observed they could best be explained by a negative inotropic effect of vagal stimulation on ventricular muscle, rather than by a d...

The cardiac metabolism of the fibrillating left ventricle of the dog heart with and without maintenance of left coronary artery inflow was investigated. During ventricular fibrillation without maintenance of coronary flow, myocardial adenosine triphosphate and glycogen fell progressively, and in vitro oxygen consumption of biopsied tissue initially increased, but with adequate coronary perfusio...