Venous circulation of the human cardiac conduction system.

Abstract

The venous bed of the sinuatrial node in 25 human hearts and the atrioventricular conduction system in 50 human hearts were investigated after injection into different veins of the heart. Blood is drained from the sinuatrial node in 2 directions; that from the intermediate and upper parts of the node blood is directed upwards, draining into the junctional area of the superior vena cava with the right atrium; that from the intermediate and the lower parts of the node is directed downwards, draining directly into the right atrium between the musculi pectinati. The venous return from the ventricular conduction system is drained by 3 routes. The main route from the atrioventricular node and the atrioventricular bundle passes into the thebesian vein, which opened in 78% of the cases into the right atrium next to the coronary sinus. Another route from the node and bundle is via a vein which accompanies the atrioventricular nodal artery, draining eventually into the middle cardiac vein. The 3rd route takes venous blood from the lower part of the atrioventricular bundle and is drained to the tributaries of the great cardiac vein, interconnecting with the branches of the above 2 veins. The venous return from the ventricular bundle-branches is drained into the oblique septal veins.