How It Is Done
This test is done in the cardiac catheterization laboratory , or "cath lab". A cardiologist will do the test.
Before the test
You will be asked to lie on a flat table under a large X-ray machine. Several small pads or patches will be attached to your legs and arms. These are called electrodes. They are connected to an electrocardiogram (EKG, ECG) machine. The machine records the electrical activity of your heart during the test.
A device called a pulse oximeter may be clipped to your finger. It measures oxygen levels in your blood. It also monitors your pulse.
An intravenous (IV) needle will be put into a vein in one of your arms. It is used for giving you fluids or medicine during the procedure. You will get medicine to help you relax (sedative) through the IV line. You may be awake during the test. But even if you are awake, the sedative may make you so sleepy that you may not remember much about the test.
During the test
The area where the catheter is put in will be shaved and cleaned before the test. Sterile towels will be draped over you, but not over the area where the catheter will be put in. There are a few options for where the catheter may be inserted. If you are having a cardiac catheterization to check the right side of your heart, the catheter is put into a vein in your neck or groin. If the test will check the left side of your heart or your coronary arteries, the catheter is put into an artery in your groin or arm.
A shot of local anesthetic will be given 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 moved through the blood vessel into your body. The catheter tip is moved into different positions in the heart's vessels and chambers while the doctor watches its progress on the imaging screen. Pressures inside the heart chambers can be measured. Blood and heart tissue samples may also be removed through the catheter, if needed.