anterior interventricular branch of left coronary artery. Terminal branch (with circumflex coronary artery) of left coronary artery; descends in anterior interventricular groove to apex, anastomosing with posterior interventricular artery. Supplies most of sternal aspect of ventricles and anterior two-thirds of interventricular septum, including atrioventricular bundle of conducting tissue. Syn: ramus interventricularis anterior arteriae coronariae sinistrae [NA], anterior descending artery.