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Cardiac Catheterization

Test Overview

Cardiac catheterization is a test to check your heart. This test uses a thin, flexible tube called a catheter that is inserted into the heart through blood vessels.

A cardiac catheterization can check blood flow in the coronary arteries. It also checks the function of different parts of the heart, such as the heart chambers, the heart valves, and the wall of the heart. In children, this test is used to check for heart problems that have been present since birth (congenital heart defect).

This test can include a coronary angiogram, which checks the coronary arteries. An angiogram is used to find out if you have disease in your coronary arteries (atherosclerosis). If you have this condition, the test can find fat and calcium deposits (plaque) that are narrowing your coronary arteries.

Sometimes percutaneous coronary intervention (PCI) is done during cardiac catheterization. It is used to open up a narrowed coronary artery with special tools. PCI is also called angioplasty.

Why It Is Done

Cardiac catheterization is done to:

  • Check on blood flow and blood pressure in the chambers of the heart.
  • Check on blood flow in the coronary arteries as part of a coronary angiogram.
  • Check on the pumping action of the heart.
  • Find out if a congenital heart defect is present and how severe it is. Cardiac catheterization sometimes can also be used to help correct the defect.
  • Check on blood flow through the heart after surgery.
  • Find out how well the heart valves work.

How To Prepare

  • Do not eat or drink (except for a small amount of water) for 6 to 12 hours before the test.
  • Before the test, remove any necklaces, bracelets, rings, or other jewellery. You should also remove nail polish from your fingernails and toenails.
  • Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
  • If you take aspirin or some other blood thinner, ask your doctor if you should stop taking it before your test. Make sure that you understand exactly what your doctor wants you to do. These medicines increase the risk of bleeding.
  • Tell your doctor ALL the medicines and natural health products you take. Some may increase the risk of problems during your test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.

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

Be sure to empty your bladder completely just 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 a machine. The machine records the electrical activity of your heart during the test.

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.

During the test

The area where the catheter is put in will be shaved and cleaned before the test. There are a few options for where the catheter may be inserted, such as the groin, arm, or neck.

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.

You may be asked to hold your breath or move your head slightly. This helps to give clear views of the heart and its blood vessels.

During an angiogram, a small amount of dye (contrast material) will be injected through the catheter into your coronary arteries. Pictures show the arteries as the dye moves through them.

Be sure to lie as still as you can, since moving can make the images blurry or hard to read. A health professional will help you stay comfortable and still.

After the test

The catheter will be removed from the site where it goes into your skin. To prevent bleeding, the site may need to be closed using pressure, stitches, or a special seal.

After the test, you will be taken to an observation room. A health professional will keep track of your heart rate, blood pressure, and temperature. You will also be checked for signs of bleeding at the insertion site. The pulse, colour, and temperature of the arm or leg in which the catheter was put in will also be checked. You may be given medicine for pain.

If the catheter was put in your groin, you may have to lie in bed with your leg extended for several hours (such as 1 to 4 hours). This depends on what procedure was used and your medical condition. After that, you can move around freely.

If the catheter was put in your arm, you may be able to sit up and get out of bed right away. But you will need to keep your arm still for at least 1 hour.

If the catheter was placed in your neck, you may be able to sit up in your bed right away.

How long the test takes

The test takes about 30 minutes. But you need time to get ready for it and time to recover. It can take up to 6 hours total. How long the test takes isn't a sign of how serious your condition is.

How It Feels

You will feel a sharp sting when you get the shot of local anesthetic to numb your skin where the catheter goes in. When the catheter is put in, you may feel a brief, sharp pain.

The movement of the catheter through your blood vessel may cause a feeling of pressure, but it usually isn't painful. People often have skipped heartbeats for a few seconds when the catheter touches the walls of the heart.

If a dye (contrast material) is injected, you may feel warm and flushed. You may have a metallic taste in your mouth. Some people feel sick to their stomach or have a headache. You also may feel nauseated or light-headed, have chest pain or pressure, irregular heartbeats, an urge to cough, mild itching, or hives from the contrast material. If you have any of these symptoms, tell your doctor how you feel.

The temperature in the cath lab is kept cool. This keeps the equipment from overheating. For many people, the hardest part of the test is having to lie still for an hour or more on the hard table. You may feel some stiffness or cramping.


Most people don't have problems during or after a cardiac catheterization.

Heart attack and stroke happen rarely, but they can be life-threatening. They are more likely to occur in older people or in people who have health conditions that raise the risk of heart attack or stroke.

Other problems that can happen during or soon after a cardiac catheterization include:

  • A tear or sudden closure in an artery.
  • An allergic reaction to the dye used to see the arteries.
  • Kidney damage related to the dye.
  • Bleeding or bruising where the catheter was put in.


Test results will be reviewed by a cardiologist. The results will be available after the test. Your doctor will be able to talk to you about some of the results right away.

Results will include whether:

  • Coronary arteries have narrowing or blockage.
  • The heart's pumping action (ejection fraction) and pressures inside the heart chambers and blood vessels are normal.
  • The heart valves are working as they should.

Many conditions can affect the results of a cardiac catheterization. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.


Current as of:
April 29, 2021

Author: Healthwise Staff
Medical Review:
Rakesh K. Pai MD, FACC - Cardiology, Electrophysiology
E. Gregory Thompson MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
Adam Husney MD - Family Medicine
John A. McPherson MD, FACC, FSCAI - Cardiology
Michael P. Pignone MD, MPH, FACP - Internal Medicine