A coronary angiogram is a special test that allows your doctor to see the arteries on your heart. Your doctor will place a small catheter in your leg or arm, and inject some dye into your arteries. An X-ray machine is then used to take pictures of the dye inside your heart. The angiogram is used to identify blockages in the arteries of the heart. Depending on the location and severity of blockages, your doctor may recommend further treatment or surgery.