Heart Disease Health Center

How To Prepare continued...

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

Arrange for someone to take you home after the test. You may not have to stay in the hospital overnight.

Do not eat or drink (except for a small amount of water) for 6 to 12 hours before the test.

Take your medicines as directed by your doctor. You might stop taking certain medicines before your test and start taking them again after your test.

Before the test, remove any necklaces, bracelets, rings, or other jewelry. You should also remove nail polish from your fingernails and toenails.

Be sure to empty your bladder completely just before the test.

How It Is Done

This test is performed in the cardiac catheterization laboratory ("cath lab") by a cardiologist. See a picture of a cardiac catheterization lab .

You will be asked to lie on a flat table under a large X-ray machine. Several small metal leads (electrodes) will be attached to your legs and arms with a special paste or gel. These leads are connected to an electrocardiogram (EKG, ECG) machine that continuously records the electrical activity of your heart during the test.

A device called a pulse oximeter that measures oxygen levels in your blood and monitors your pulse may be clipped to your finger.

An intravenous (IV) needle will be inserted into a vein in one of your arms to give you fluids or medicine during the procedure. You will receive a medicine to help you relax (sedative) through the IV line. You may be awake during the procedure. But even if you are awake, the sedative may make you so sleepy that you may not remember much about the procedure.

The thin flexible tube (cardiac catheter) is usually inserted in your groin (femoral artery). Other sites that may be used are the crease of your elbow (brachial artery), your wrist (radial artery), or your neck. The catheter insertion area will be shaved and cleansed with an antiseptic solution before the test. Sterile towels will be draped over you, except for the area over the catheter insertion site.

A local anesthetic will be injected into the skin at the insertion site. A blood vessel is punctured by a special needle or exposed by making a small cut in the skin so that the catheter can be passed into the blood vessel. The catheter is slowly advanced through the blood vessel into your body. The catheter tip is moved into various positions in the heart's vessels and chambers while the doctor watches its progress on the imaging screen. Pressures within the heart chambers can be measured. Blood and heart tissue samples may also be removed through the catheter, if necessary.