Dominant Left Coronary Artery

The left coronary angiogram in this instance demonstrates a dominant left system. Both the anterior and posterior component of the circumflex, overlaid in red in b, are of a large caliber. In c, the first second third and fourth obtuse marginals are shown. In d the origin of the PDA, posterior left ventricular branch, and the AV nodal artery are shown at the crux of the heart. Since the inferolateral portion of the heart and the A-V nodal artery arise from the left coronary artery it is a left dominant system (about 10% of cases).
Courtesy: Ashley Davidoff, M.D.