During the course of your evaluation, your doctor may suggest cardiac catheterizaton for more detailed evaluaton of your coronary arteries, heart muscle function, valvular function, or extremity blood vessels.  Catheterization is performed in the hospital, and requires placement of a small tube in your blood vessel either in the arm or leg under local anesthesia.  During the procedure, angiogram dye is used to visualize the various structures with the aid of flouroscopy, and pressures are recorded.  The procedure may take from 20 minutes to several hours.  If significant artery blockages are found, they are frequently treated at the same time.  You may be required to stay in the hospital overnight if stents are placed.  Sedation is administered as necessary to assure your comfort.