Cardiac catheterization is a procedure that can provide a great deal of valuable information about the anatomy and function of the heart. The procedure can have several components, including the direct measurement of blood pressure in each of the heart chambers, the visualization of the coronary arteries, and the measurement of heart function.

An important component of this procedure is the coronary angiogram. This is a test used to examine the coronary arteries. During the angiogram, a long, flexible tube called a catheter is inserted into a vein in the patient’s arm or leg. The tube is then guided into the chambers of the heart or the coronary arteries. This allows the provider to take a close look at the inside of the heart muscle, to measure blood pressure within the heart, and to determine how much oxygen is in the blood.

During the procedure, contrast media, which is a dye that shows up on X-ray, is injected into the blood vessel. An X-ray is taken, and the blood vessels and heart are filmed as the heart pumps. The resulting picture, called an angiogram or arteriogram, will show arteries that are blocked due to atherosclerosis as well as the extent of the blockage. Dye can also be directly injected into the left ventricle to determine the ejection fraction. The ejection fraction is the proportion, or fraction, of blood pumped out of the heart with each beat.