DefinitionCardiac catheterization involves passing a thin flexible tube (catheter) into the right or left side of the heart, usually from the groin or the arm.Alternative NamesCatheterization - cardiac; Heart catheterizationHow the test is performedYou will be given a mild sedative before the test to help you relax. An intravenous (IV) line is inserted into one of the blood vessels in your arm, neck, or groin after the site has been cleansed and numbed with a local numbing medicine (anesthetic).A catheter is then inserted through the IV and into your blood vessel. The catheter is carefully threaded into the heart using an x-ray machine that produces real-time pictures (fluoroscopy). Once the catheter is in place, your doctor may:Collect blood samples from the heartMeasure pressure and bloo