What Is It? Cardiac catheterization is a procedure in which a
heart specialist inserts a small tube (catheter) through a large
blood vessel in the arm or leg, and then passes the tube into
the heart. Once inside the heart, doctors use the catheter to
evaluate how the heart is working by measuring pressure and
oxygen levels within the heart's chambers. Through the catheter,
doctors inject a special dye that provides an X-ray image of the
heart's internal structure and blood flow patterns. In some
patients, the X-ray dye also is injected into the coronary
arteries to identify areas that have become narrow. This
procedure is called coronary angiography. What It's Used For
Cardiac catheterization is used to evaluate patients who: - May
have suspected coronary artery disease - Are having a heart
attack or in immediate danger of having a heart attack - Will be
undergoing heart surgery, especially coronary artery bypass
surgery - May have suspected coronary artery disease - Have
heart valve problems, including abnor