Cardiac catheterization is a minimally invasive procedure in which a long, thin tube called a catheter is guided into the heart, most commonly passed through an artery in the groin. Once inside the heart, it can be used for diagnostic purposes to assess blood supply to the heart as well as the function of the heart's main pumping chamber (left ventricle). It can also be used to perform therapeutic interventions to correct a problem. This article deals with the diagnostic uses of cardiac catheters.

By gaining access to the beating heart, cardiac catheters can provide valuable information. Using a catheter, a physician can check the internal blood pressure of the heart, get a good look at the coronary arteries on the surface of the heart, and (depending on where the catheter is positioned) the aorta. Catheters are also used to monitor the electrical activity in the heart to diagnose arrhythmias and plan treatments.

During the cardiac catheterization, a physician inserts the catheter into a patient’s blood vessel (usually in the groin) and passes the tube toward the heart. Depending on where the catheter is placed, and which test is performed, the test can yield a wide range of information about the arteries connected to the heart and the structures of the heart itself. The procedure can help a physician identify narrowed or clogged arteries, evaluate the heart’s four valves, and assess for any congenital heart defects. Cardiac catheters can also be used to measure the blood pressure within the heart itself, or measure the amount of oxygen in the blood.

The cardiac catheterization may include four major components: