Cardiac Catheterization

Discusses test used to check your heart and coronary arteries. Covers reasons cardiac catheterization is done. Looks at how to prepare. Explains how the test is done in the cardiac catheterization laboratory (cath lab) by a cardiologist. Covers risks.

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Cardiac Catheterization

Test Overview

What is Cardiac catheterization?

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. This test can include a coronary angiogram, which checks the coronary arteries.

Why would you need a cardiac catheterization?

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).

A coronary 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.

Percutaneous coronary intervention (PCI) is similar to a coronary angiogram. But it is used to open up a narrowed coronary artery with special tools. PCI is also called angioplasty.

What does the cardiac catheterization reveal?

Results from a coronary angiogram help to find out if certain treatments are likely to work for you. This includes treatment with medicines, bypass surgery, or percutaneous coronary intervention (PCI), such as angioplasty.

For help deciding about having this test for coronary artery disease, see Heart Disease: Should I Have an Angiogram?

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Why Cardiac Catheterization Is Done

Cardiac catheterization

Cardiac catheterization is done to:

  • Check blood flow and blood pressure in the chambers of the heart.
  • Check 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 blood flow through the heart after surgery.
  • Find out how well the heart valves work.

Coronary angiogram

A coronary angiogram is done to:

  • Check blood flow in the coronary arteries. If you have coronary artery disease, the test helps to find out if you may need surgery or another type of procedure, such as angioplasty with stenting.

How To Prepare

Tell your doctor if you:

  • Are having an angiogram and are allergic to the iodine dye used in the contrast material or any other substance that contains iodine.
  • Are allergic to anything that might be used during the test, such as latex or talc.
  • Are allergic to any medicines.
  • Take any medicines, vitamins, supplements, or herbal remedies. Some of these can raise your risk of bleeding. Some medicines can cause other problems during the test. Your doctor will tell you which medicines to stop before your test and which medicines you can take safely. Medicines to mention include:
    • Aspirin or some other blood thinner.
    • Erection medicines, such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra).
  • Are pregnant, might be pregnant, or are breastfeeding.
  • Have asthma or have ever had a serious allergic reaction (anaphylaxis) from any substance, such as the venom from a bee sting.
  • Have any bleeding problems.
  • Have kidney disease. The contrast material used during an angiogram can cause kidney damage in people who have poor kidney function. If you have a history of kidney problems, blood tests may be done before and after the test to make sure that your kidneys are working well.

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 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, groin, or arm. 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.

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. You may be asked to cough to help clear the contrast material out of your heart. Or you may be asked to take a deep breath and hold it.

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. Be careful not to touch the sheets or the area where the catheter is inserted. If you do, you may contaminate the clean areas and increase the risk of infection.

You may be given nitroglycerin. This helps open up your coronary arteries. Or you may get a shot of a medicine that causes the coronary arteries to narrow. You may be asked to breathe into a special mouthpiece. This helps to measure the flow of oxygen in your blood.

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 is not a sign of how serious your condition is.

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. For example, if the catheter was put in your wrist or groin, firm pressure will be applied to that area for about 10 minutes to stop the bleeding. Then a bandage or a compression device may be placed on your groin or wrist at the catheter insertion site. If the catheter was put in your elbow, a few stitches will be used to close the wound.

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

A child who has had cardiac catheterization may need to be held by a parent for several hours after the test. This is to prevent the child from moving his or her leg.

You should drink plenty of liquids for several hours after the test. This will prevent dehydration. And it will help flush the contrast material out of your body.

Depending on the results of the test, you may be sent home either after being observed for a short time (such as 6 hours) or the next day. If you got any stitches in your arm, they may be removed in 5 to 7 days. Do not do strenuous exercise or lift anything heavy until your doctor says it is okay. This may be for a day or two.

If you are breastfeeding and had an angiogram in which dye was put into your body, use formula for 2 days after this test. Discard the breast milk you pump for 2 days after the test.

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 is not usually 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 lightheaded, 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.

After you go home

You may have some soreness and bruising at the insertion site. This is temporary and should go away within 2 weeks. It is normal for the site to feel tender for about a week.

Call your doctor right away if:

  • Your leg, arm, or hand gets pale, cold, painful, or numb.
  • You have a fast-growing, painful lump where the catheter went in.
  • You get redness, swelling, or discharge where the catheter went in.
  • You have a fever.


Most people do not have problems during or after an angiogram.

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

Other problems that can happen during or soon after an angiogram 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.

Conditions that can raise risk of problems

Certain health conditions can raise your risk of having problems after angioplasty. Conditions that can raise the risk of death from the procedure include heart failure, heart valve problems, and chronic kidney disease. The risk of heart attack may be higher if you have heart disease in the left main coronary artery.

Having these conditions doesn’t mean that you will have a problem from the procedure. You and your doctor can talk about whether your risk of a problem is higher than average.

Radiation risk

There is always a slight risk of damage to cells or tissues from being exposed to any radiation. This includes the low levels of X-ray used for this test.

Some evidence suggests that the radiation used in this test could raise the risk of getting cancer later in life. But the risk is believed to be about the same as from many everyday activities and medical procedures. The risk of damage from the X-rays is usually very low compared with the possible benefits of the test.


Cardiac catheterization is a test to check your heart and coronary arteries.

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.

What Affects the Test

You may not be able to have the test, or the results may not be helpful, if:

  • You are very anxious. This may cause high blood pressure and irregular heartbeats.
  • You have kidney or liver failure.
  • You are not able to follow directions during the test.

What To Think About

  • This test usually is not done on people who have had severe allergic reactions to contrast material, poorly controlled heart failure, life-threatening heart rhythm problems, or advanced kidney disease.
  • Cardiac catheterization is not usually done during pregnancy. This is because the radiation could damage the developing fetus. But in a life-threatening emergency, this test may be needed to help save a pregnant woman’s life. In such cases, a lead apron is used to protect the fetus as much as possible from the radiation.


Other Works Consulted

  • Balaji NR, Shah PB (2012). Radial artery catheterization. Circulation, 124(16): e407–e408.
  • Bangalore S, Bhatt DL (2011). Right heart catheterization, coronary angiography, and percutaneous coronary intervention. Circulation, 124(17): e428–e433.
  • Bashore TM, et al. (2012). 2012 ACCF/SCAI Expert consensus document on cardiac catheterization laboratory standards update. Journal of the American College of Cardiology, 59(24): 2221–2305.
  • Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
  • Glowny MG, Resnic FS (2012). What to expect during cardiac catheterization. Circulation, 125(7): e363–e364.


Current as ofApril 9, 2019

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

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