ON THE RELATION OF THE VOLUME OF THE CORONARY CIRCULATION TO THE FREQUENCY AND FORCE OF THE VENTRICULAR CONTRACTION IN THE ISOLATED HEART OF THE CAT

EFFECT OF VARIOUS AGENTS ON THE BLOOD FLOW THROUGH THE CORONARY ARTERIES AND VEINS

The results obtained show that adrenalin, transfusion with salt solution, and the inhalation of tobacco smoke caused an increased circulation in the coronary vessels. Amyl nitrite and nitroglycerin produce the opposite effect. Digitalis, strophanthus, caffeine, and theobromine give no change in the velocity of circulation. We can conclude from the results that the blood pressure is the main element which influences coronary circulation, while the other factors play only a minor part in its variations.

The Experimental Production of Intercoronary Arterial Anastomoses and their Functional Significance

Animal experiments were done to learn the degree of coronary narrowing required to produce the larger intercoronary collateral channels, their speed of development, and the degree of protection afforded the myocardium. Twelve or more days of 75 per cent narrowing were required to produce sufficiently rich anastomotic communications to protect the myocardium from damage, and to permit survival after superimposed acute complete occlusion. The physiologic and pathologic significance of the intercoronary collateral communications and the clinical implications in coronary artery disease are discussed.