Cardiac catheterization, also known as cardiac cath or heart catheterization, is a medical procedure used to diagnose and treat some heart conditions. It lets doctors take a close look at the heart to identify problems and to perform other tests or procedures.

Your healthcare provider may recommend cardiac catheterization to find out the cause of symptoms such as chest pain or irregular heartbeat. Before the procedure, you may need to diagnostic tests, such as blood tests, heart imaging tests, or a stress test, to determine how well your heart is working and to help guide the procedure.

During cardiac catheterization, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin or upper thigh, or neck. The catheter is then threaded through the blood vessels to your heart. It may be used to examine your heart valves or take samples of blood or heart muscle. Your doctor may also use ultrasound, a test that uses sound waves to create an image, or they may inject a dye into your coronary arteries to see whether your arteries are narrowed or blocked. Cardiac catheterization may also be used instead of some heart surgeries to repair heart defects and replace heart valves.