A cardiac catheter is a thin, flexible tube used by doctors to diagnose and treat heart conditions. It is inserted into a blood vessel and guided to the heart, allowing doctors to measure blood pressure, take samples, and even perform procedures like opening blocked arteries. This technique helps in understanding how well the heart is functioning. During a cardiac catheterization procedure, patients are usually given a local anesthetic to minimize discomfort. The procedure is often done in a hospital's catheterization lab, and while it may sound intimidating, it is generally safe and can provide valuable information about heart health.