The heart is a tireless organ just slightly larger than one's clenched fist. Normally the heart beats one hundred thousand (100,000) times every 24 hours to distribute blood throughout the body, bringing the oxygen necessary to nourish organs and muscles.

The right side of the heart receives blood with a low oxygen content from the body. The right heart then pumps this blood to the lungs, where carbon dioxide is removed and the blood is enriched with oxygen. The blood then returns to the main pumping chamber of the heart, the left ventricle. The left ventricle ejects the blood out the main artery of the body, the aorta, for distribution to all of the organ systems of the body.

Adequate function of the heart involves a normal muscle with normally functioning valves, a normal electrical system of the heart which is used to activate the pumping process and finally the coronary arteries, which supply nourishment to the muscle of the heart itself. An insufficiency with any of these systems - muscle, valves, electrical, or coronary arteries - can lead to significant problems.

Once the patient's cardiac function is carefully evaluated through examination and other non-invasive studies, a cardiac catheterization may be performed to specifically delineate the exact problem. Most catheterizations today are performed to evaluate the status of the coronary arteries, i.e., are these vessels wide-open or are they significantly narrowed by arteriosclerosis or "hardening of the arteries"?

The catheter would pass through the aorta into the blood vessels located on the surface of the heart, known as the coronary arteries. Dye injected into the blood vessels would be seen on x-ray. Any reduction in blood supply would show up as a narrowing or constriction of the blood vessel. Additionally, the catheter would pass inside the heart to assess the function of the heart valves, and finally into the cavity of the heart where the muscle pumping action of the heart could be evaluated.

Depending upon the presence and extent of hardening of the arteries, the patient could be treated with medication, surgery, or one of the balloon-catheter interventions.