Control of the coronary circulation by the carotid sinus was studied in intact, unanesthetized dogs instrumented with Doppler ultrasonic flow probes on the left circumflex coronary artery, miniature pressure gauges in the aorta, and stimulating electrodes on the carotid sinus nerves. A radiofrequency pacemaker was used to stimulate the nerves in dogs at rest, during sleep, exercise, and after a...

T coronary-sinus reduction described by Verheye et al. in this issue of the Journal (pages 519–527) revives an old therapeutic concept. Between 1948 and 1968, Cleveland surgeon Claude Beck performed coronary-sinus ligation in more than 1000 patients, aiming to improve myocardial oxygenation. Despite Beck’s reports of impressive efficacy, few surgeons adopted his techniques. The history of this ...

BACKGROUND The aim of the study was to establish the influence of proximal coronary artery atheroma and smoking habit on the stimulated release of tissue plasminogen activator (tPA) from the heart. METHODS AND RESULTS After diagnostic coronary angiography in 25 patients, the left anterior descending coronary artery (LAD) was instrumented, and the proximal LAD plaque volume was determined by u...

A comparative study is presented on the circulatory dynamics of the renal hypertensive state, the stability (repeatability) of the findings in a given subject, the effect of anemia as a complicating factor and the amount of cardiac hypertrophy present in each animal at the end of the series of observations. The results indicate that in nonanemic renal hypertensive dogs with cardiac hypertrophy ...

The ability to study the oxygen arterio-venous difference in the heart and to measure coronary blood flow has led to a unique concept of the way in which oxygen demands of the heart are met. The coronary sinus oxygen content is low and apparently constant in health and in a wide variety of diseases (anemia, arterio-venous fistula, hyperthyroidism), and oxygen demand is met by increased blood fl...

We tested the hypothesis that potassium ion (K+) is involved in the local control of the coronary circulation. The left coronary artery was perfused at constant flow in closed-chest, anesthetized dogs. Step increases in heart rate caused transient (six dogs) or sustained (three dogs) increases in coronary sinus plasma [K+] averaging 0.53 mEq/liter. When the effects of vascular transit delay wer...

a substantial decrease in myocardial contractility. This was reflected by a fall i cardiac index (average of 0.6 L/min/M2, P < 0.001) and of arterial mean pressure (average of 16 mm Hg, P < 0.001) with little change in systemic vascular resistance. Decrease in cardiac index was due mainly to decrease in stroke volume. Heart rate, not strikingly increased at the control state in the majority of ...

a substantial decrease in myocardial contractility. This was reflected by a fall i cardiac index (average of 0.6 L/min/M2, P < 0.001) and of arterial mean pressure (average of 16 mm Hg, P < 0.001) with little change in systemic vascular resistance. Decrease in cardiac index was due mainly to decrease in stroke volume. Heart rate, not strikingly increased at the control state in the majority of ...

Acute aortic valvular insufficiency was induced in open chest dogs by employing a special intravascular cannula, or by rupturing an aortic valve leaflet. Phasic and mean coronary flow were assessed in some animals, while in others data were obtained on arterial and coronary sinus blood lactate, pyruvate, P(O2), P(CO2), and pH, and on myocardial tissue lactate, pyruvate, and water content in the...