A note on some factors which determine the blood-flow through the coronary circulation.
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TL;DR: Of the methods so far adopted it seems to us that the best is that devised by Morawitz, which has been constructed a double-valled cannula with a bulbous extremity which enters easily the coronary sinus.
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Abstract: VARIOUS methods have been employed for the investigation of the coronary circulation. Bohr and Henriquez(i) judged of the amount of blood flowing through these vessels by comparing the total outflow through the aorta and the pulmonary artery respectively in a heart fed for a few minutes with defibrinated blood. Brodie and CUllis(2), as well as Wiggers(3), employed excised hearts perfused with Ringer's fluid. Langendorff(4) and Cow(5) examnined the behaviour of strips of the coronary artery immerse(d in Ringer's fluid. Meyer(6) determined the outflow frorn a cannula placed in one of the superficial coronary veins. Of the methods so far adopted it seems to us that the best is that devised by Morawitz(7). This observer catheterises the coronary sinus in the living heart. For this purpose he has had constructed a double-valled cannula with a bulbous extremity which enters easily the coronary sinus. Just behind the bulbous end is a hole communicating with the outer chamber of the cannula. Over this hole is a ring of rubber membrane. Fluid can be forced througlh a side tube into the outer chamber so as to distend the rubber ring. The cannula is inserted through the right auricular appendix, escape of fluid being prevented by tying the tip of the appendix tightly round the stem of the cannula. The introduction of the cannula into the coronary sinus presents no difficulty, and its end can be felt and seen as it enters the thin-walled sinus. When it has been introduced the rubber ring is distended, thus fixing the cannula firmly in the mouth of the coronary sinus. The other end of the cannula has attached to it a tube which passes through the right thoracic wall. From this tube the blood drops either into a measuring cylinder or on to some volume counter. Of course it is necessary to prevent coagulation of the blood by the injection
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Citations
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Influence of dipyridamol (Persantin) on myocardial adenosine metabolism
TL;DR: The diffusion of adenosine from the intracellular to the extracellular space cannot be essential for the coronary dilating action of dipyridamol and, therefore, not for the local metabolic regulation of coronary blood flow.
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Carbon Dioxide and the Heart: Physiology and Clinical Implications.
TL;DR: Clinically relevant issues are addressed, including the role of increased myocardial tissue PCO2 (PmCO2) in the decline in myocardIAL contractility during coronary hypoperfusion and the increased vulnerability to CO2-induced cardiac depression in patients receiving a &bgr;-adrenergic receptor antagonist or with otherwise compromised inotropic reserve.
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Relative effect of CO2 on canine coronary vascular resistance.
TL;DR: The entire range of CVR variation obtainable through CO, variation was as great as that resulting from O, variation, during randomized variation of O, and CO2 CVR.
67
References
The part played by the lungs in the oxidative processes of the body.
TL;DR: These results have been criticised by Zun tz and Hagemann (5) and by Loewy and Zuntz (6), who doubt whether the blood-samples collected really were representative ones.
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On a simple form of stromuhr.
H. Ishikawa,E. H. Starling +1 more
TL;DR: In a paper recently published by one of us with Prof. Knowlton, a method was described in which the outflow of blood from a circulation apparatus, and therewith the output of the heart, was determined by allowing the blood to flow into a vessel from which it was siphoned off as soon as it attained a certain mark.
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