A very rare anatomic variation of the right ventricular branch: right ventricular descending branch from the anterior interventricular branch.

The anterior interventricular branch of the left coronary artery has the most constant distribution in the human heart and rarely gives off right ventricular branches. Here we report a case with a right ventricular branch which diverged from the anterior interventricular branch and descended on the anterior right ventricular wall parallel to the anterior interventricular sulcus; we termed it the "right ventricular descending branch." This artery gave a collateral artery to the occluded anterior interventricular branch at the apex, and had prevented anterior myocardial infarction. The right ventricular descending branch should be precisely identified in order to perform successful myocardial revascularization procedures such as coronary artery bypass grafting and percutaneous coronary intervention, especially in a patient with anterior interventricular branch occlusion.