Cardiac catheterization is a medical procedure used to diagnose and treat heart conditions. During the procedure, a thin, flexible tube called a catheter is inserted into a blood vessel, usually in the arm or leg, and guided to the heart. This allows doctors to measure blood pressure, take images, and assess the heart's function. The procedure can also be used to perform treatments, such as opening blocked arteries with a stent or taking tissue samples for further analysis. It is typically done in a hospital setting and may require sedation to ensure patient comfort.