Cardiac catheterization of a man with severe angina and anterior ischemia on exercise testing with perfusion imaging demonstrated normal anterior wall motion resting left ventriculography, but failed to visualize the left anterior descending (LAD) or conus artery on left and right coronary angiography. Selective contrast injection of a large conus artery originating from a separate ostium in the right aortic sinus demonstrated extensive collateral circulation to an LAD occluded at its origin from the left main coronary artery, thus providing essential information for subsequent patient management.