Collateral circulation via a rare, anomalously arising right ventricular branch.

Variations in coronary anatomy are not uncommon. They are usually benign, but can be a cause of confusion to the angiographer and in most situations, have no clinical significance. In this report, we present an unusual case of a chronically occluded proximal right coronary artery with an anomalous separate right ventricular branch arising directly from the aortic root and serving as a large collateral to the area beyond the occlusion. To our knowledge, this is the first of such anatomic variations being reported.