Cardiac catheterization is a diagnostic procedure that produces moving images of the heart. Cardiologists review these images to assess an individual's cardiac health.

The catheterization procedure involves the injection of dye into the chambers and vessels of the heart. When imaged with special x-ray equipment, the dye allows the pumping action of the heart, the function of the heart valves, and blood flow in the coronary arteries to be captured in a digital "movie."

Dye is injected into the heart through a catheter (a long, thin, flexible tube) into the heart. The catheter is introduced into the body through a vein or artery, usually in the leg, and guided by the cardiologist to the heart. Sophisticated x-ray technology is used to monitor the insertion and removal of the catheter. Once the catheter is properly positioned inside the heart, the dye is released.

Other terms used to describe cardiac catheterization include coronary angiography, angiogram, and cardiac (or heart) cath.