A catheter (CATH-uh-ter) is a thin, hollow tube that's inserted
in the body, so it can deliver or carry away some substance. In
cardiac catheterization (cath-uh-ter-eye-ZAY-shun), the tube is
inserted through a blood vessel in the groin, and guided by
x-ray to the heart. Typically, a special dye is then introduced
into the tube, where it travels to the coronary arteries. This
procedure is known as coronary angiography (ann-jee-OG-rah-fee).
Doctors can trace the path of the dye on the x-ray monitor, thus
discovering any blockages. In addition, they may gather
information on the heart's overall function, including blood
flow and valve operation. Cardiac catheterization is relatively
painless, and is performed in the lab under mild sedation. After
the nurse removes the catheter, pressure is applied for about 30
minutes to stop bleeding at the site. The patient usually spends
the day resting in bed. While the procedure is not without risk,
it remains the most effective test available for diagnosing
heart disease