The descending septal artery. Its relation to the conduction system of the heart.

The blood supply to the upper ventricular septum in the region of the conduction system is more abundant than the literature suggests. I found a significant arterial contribution to the upper ventricular septum from the proximal segment of the right coronary artery (RCA), or one of its early branches, in 77% of 65 hearts examined. Descending septal arteries (DSAs) supplied the region of the proximal conduction system in 68% of the hearts, about half of which demonstrated severe coronary arteriosclerosis. The influence of the DSA on the pathogenesis and subsequent course of conduction defects due to occlusive coronary artery disease remains to be evaluated. My results indicate that the preexisting blood supply derived from proximal RCA, from one or more of its early branches, or directly from the aorta plays an important role in this respect.