An unusual case of an obtuse marginal branch supplying the left ventricular apex.

In most patients, the left anterior descending coronary artery (LAD) feeds the anterior aspect of the interventricular septum and a large segment of the anterior wall of the left ventricle. It then passes around the left ventricular apex to supply that area as well. However, in some cases, the LAD is shorter and terminates either at or before the left ventricular apex. The latter in these cases is instead supplied by a long posterior descending coronary artery (PDA), originating from the right coronary artery (RCA) at the crux, then passing along the entire length of the posterior interventricular groove, and either terminating at the apex or extending beyond it to pass upward in the anterior interventricular groove. In this case report, we describe a 50-year-old man with an apical perfusion defect on stress myocardial perfusion imaging in whom diagnostic coronary angiography revealed that the left ventricular apex was supplied by a large, obtuse marginal branch of the left circumflex coronary artery (LCX) instead of the LAD.