Pressure and flow in epicardial coronary veins of the dog heart: responses to positive inotropism

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Abstract
Peripheral coronary venous pressures and coronary sinus venous flow were measured in the canine heart as well as intramyocardial, intraventricular, aortic and coronary artery pressures. Maximum coronary venous flow occurred after maximum intramyocardial and peripheral coronary artery pressures were reached. Maximum venous flow occurred at or following the maximum peripheral coronary vein pressure. Positive inotropic changes induced by stimulation of the right or left stellate ganglia or infusing isoproterend, norepinephrine or dobutamine significantly increased intramyocardial pressure, systolic epidcardial coronary venous pressure, and systolic coronary venous flow. Mean coronary sinus flow was augmented by all interventions except isoproterenol. The estimated systolic vein resistance was slightly increased following right stellate ganglion stimulation, but not following left stellate ganglion stimulation, isoproterenol or dobutamine. Norepinephrine reduced this parameter minimally. Evidently, coronary veins respond differently to a variety of different positive inotropic interventions.