Cardiac catheterization is a technique that is used in several different tests and procedures. It is usually used in conjunction with other tests such as angiography and electrophysiology studies.

Cardiac catheterization is normally used to evaluate heart valves, heart function and blood supply, as well as heart abnormalities in newborns. It may also be performed to determine whether or not you need heart surgery. As well, cardiac catheterization may be used therapeutically to repair a heart defect, perform heart grafts, or open a stenotic heart valve or blocked arteries.

What is involved

A thin flexible tube called a catheter is passed through an artery or vein at the top of the leg (groin) or in the arm to reach the heart. Then X-rays are used to see the blood vessels and heart. The catheter also measures the pressure inside your heart and blood vessels and can determine if blood is mixing between the two sides of the heart.

Sometimes, a dye is injected through the catheter to see the heart and its arteries (coronary angiography). This lets your doctor see the flow of blood through your heart and blood vessels. Controlled electrical impulses may also be sent through the catheter to see how your heart reacts, or to trigger irregular heartbeats (electrophysiology studies).

What to expect

You will lie on an examination table. Small metal disks called electrodes will be placed on your chest, connecting to an electrocardiogram machine that monitors your heart rhythm during the test. You will be set up with an IV (intravenous line) to give you a sedative to help you relax. The area where the catheter will be inserted will be cleaned. Then an anesthetic will be used to numb the area. The catheter is then put into the artery in your leg or arm then threaded through to your heart. You should not feel pain during this part of the test. Once the test is complete, the catheter and IV will be removed. The total time for the procedure inside the lab is between 30 minutes and one hour. After the procedure, the doctor will remove the catheter from your groin area or arm and apply pressure, using a special clamp. This will take approximately 20 minutes. You must remain on bed rest for 4 to 6 hours after the procedure. It may also involve a hospital stay of one to two nights.

How to prepare

You will probably be told not to eat or drink anything after midnight the night before your catherization. If you have diabetes, talk to your doctor about how to prepare for the test including when you should eat and take your insulin or other medications. Tell your doctor about all medications including prescription medications such as blood-thinners and anti-platelets, as well as any over-the-counter medications. You may want to make a list of your medications and dosages to take with you to the test. It is important to speak to your doctor about how to prepare for the test, specifically about food, drink and medications. If you have questions, it is best to check with the centre where you are having your test for specific information about how to prepare.