Cardiac catheterization and angiogram. During cardiac catheterization, a heart doctor (cardiologist) gently inserts a flexible tube (catheter) into a blood vessel, usually in the wrist or groin. The catheter is gently guided to the heart. X-rays help guide it. Dye flows through the catheter. The dye helps blood vessels show up better on the images and outlines any blockages.
If you have an artery blockage that needs treatment, a balloon on the tip of the catheter can be inflated to open the artery. A mesh tube (stent) is typically used to keep the artery open.