A cardiac catheter is a thin, flexible tube used to diagnose and treat heart conditions. It is inserted into a blood vessel and guided to the heart, allowing doctors to measure pressures, take blood samples, and visualize the heart's chambers and arteries using imaging techniques. During a cardiac catheterization procedure, a local anesthetic is applied, and the catheter is typically inserted through the femoral artery in the groin or the radial artery in the wrist. This procedure helps identify issues such as blockages or abnormalities in the heart, guiding treatment decisions.