Cardiac Catheterization (Cath) is a specialized study of the heart during which a catheter, or thin hollow flexible tube, is inserted into the artery of the groin or arm. Under X-ray visualization, the tip of the catheter is guided to the heart. Pressures are measured and an x-ray Angiogram (Angio) movie of the heart and blood vessels are obtained while injecting an iodinated colorless "dye" or contrast material through the catheter. Coronary angios are obtained by injecting the contrast material into the opening or mouth of a coronary artery. The iodinated solution blocks the passage of x-rays. X-ray movie pictures taken during the injection of the contrast material allow the coronary arteries to be visualized. In other words, coronary arteries are not visible on x-ray film. However, they can be made temporarily visible by filling the coronary artery with a contrast solution that blocks x-ray.

   The coronary arteries are vital because they supply oxygen and nutrients to the heart muscle. Without blood flow, the muscle would sustain permanent damage in the form of a heart attack or myocardial (pronounced my-ow-card-yull) infarction (pronounced in-fark-shun).

Cardiac Catheterization (Cath) is also known as Heart Cath, Angiogram (Angio) (pronounced an-gee-o-gram) or Arteriogram (pronounced ar-tee-rio-gram). The latter two terms describe the use of contrast material to take x-ray pictures of the heart.