Abstract
It has been suggested by Gross, 1 Robertson, 2 and Ungerleider 3 that ligation of the coronary sinus or coronary veins might materially aid hearts whose normal blood supply had been partially removed. Fortunately, such a concept can be tested physiologically and hence an experimental study was made of the possible practical value of such a procedure.
In order to obtain a better understanding of what happens dynamically in the coronary vascular bed following ligation of the coronary venous system, the following have been studied in 28 acute experiments on dogs and largely by optical methods: (1) the coronary inflow, (2) the peripheral coronary pressure, (3) intravenous pressure, (4) the retrograde blood flow in the coronary arteries, together with oxygen determinations, (5) the ability of the myocardium to maintain contractions after its normal blood supply has been removed. The results which have been obtained follow.
After coronary sinus ligation the reduction in coronary inflow (by the method of differential pressure curves) is considerable in the left coronary, but not in the right.
The contour and time relations of the peripheral coronary pressure are similar to those obtained under normal conditions 4 but both the diastolic and systolic resistances are greatly elevated in the left coronary. The latter value approaches, equals or exceeds the aortic systolic pressure simultaneously recorded. This pressure increment has its source largely in the other non-occluded coronaries.
The intravenous pressure (in a coronary vein or in the coronary sinus) rises from control values of say 10/2 mm Hg. to figures which during systole approach or exceed the aortic systolic and whose diastolic value reaches 20 to 40 mm Hg. This pulse is patterned in time and contour after the peripheral coronary pressure while its ordinate values are generally slightly greater.
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