The anatomic variability of the coronary vasculature of the human heart--part II: some anatomical peculiarities of arteriovenous relations.

The arteriovenous relations in human heart are, in some instances, different from arteriovenous relations in other parts of the body. The specific relations between cardiac arteries and veins may enable diffusible substances carried through the system of juxta-arterial cardiac veins to influence the regulation of the lumen of the coronary arteries. Arteriovenous anastomoses (6% of our 150 cases) permit direct communication between the arteries and veins bypassing the capillary circulation; it is assumed that these anastomoses prevent coagulation of blood in small veins. In cases of arterial occlusion, the myocardium is supplied by veins that allow retrograde vascularization of the myocardium. In 33% of our cases the posterior atrial branches (0.5-1.0 mm in diameter) of the coronary arteries ran through the wall of the coronary venous sinus on their way from the parent vessel, which lay in the coronary sulcus, to the left atrium. In 11% of the cases, the arterial branch that ran through the distal portion of the wall of the coronary sinus was the interatrial branch. The blood flow through the parietal arteries of the venous coronary sinus probably depends on the condition of the muscular layer of the sinus during the phases of cardiac action, and this might be important in the course of certain cardiosurgical procedures.