Cardiac Catheterization

Also known as Cardiac cath, Heart catheterization
Cardiac catheterization is a medical procedure used to diagnose and treat some heart conditions. It lets doctors take a close look at the heart to identify problems and perform other tests or procedures on your heart.

Your doctor may recommend cardiac catheterization to find out the cause of symptoms such as chest pain or irregular heartbeat, or to find out whether you have ischemic heart disease due to blockages in the coronary arteries. Before the procedure, your doctor may need to do diagnostic tests, such as blood tests, heart imaging tests, or a stress test, to determine how well your heart is working and to help guide the procedure.

During cardiac catheterization, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin or upper thigh, or neck. The catheter is then threaded to your heart. Your doctor may use it to examine your heart valves or take samples of blood or heart muscle. Your doctor also may use ultrasound or inject a dye into your coronary arteries to see whether your arteries are narrowed or blocked. Cardiac catheterization may also be used instead of some heart surgeries to repair heart defects and replace heart valves.

Cardiac catheterization is safe for most people. Complications are rare but can include bleeding and blood clots. Your doctor will monitor your condition and may recommend medicines to prevent blood clots.

Explore this Health Topic to learn more about cardiac catheterization, our role in research and clinical trials to improve health, and where to find more information.

Who Needs It - Cardiac Catheterization

Your doctor may recommend cardiac catheterization to find out what is causing signs or symptoms of a heart problem or to treat or repair a heart problem. Cardiac catheterization is safe for most people.

Your doctor may recommend cardiac catheterization to help with diagnoses or plan treatment. It can be useful when your doctor wants to do any of the following:

Your doctor may perform additional procedures to diagnose or treat your condition during cardiac catheterization. Some of these procedures include:

  • Biopsies to take small samples of the heart tissue for further laboratory testing. Biopsies can be used for genetic testing or to check for myocarditis, a type of heart inflammation, or transplant rejection.
  • Coronary angiography to look at the heart or blood vessels by injecting dye through the catheter.
  • Minor heart surgery to treat congenital heart defects and replace or widen narrowed heart valves.
  • Percutaneous coronary intervention (PCI) to open narrowed or blocked areas of the coronary arteries. PCI may include balloon dilation, or angioplasty, or stent placement. Most people who have heart attacks or underlying ischemic heart diseases have narrowed or blocked coronary arteries.

Who should not have cardiac catheterization?
- Cardiac Catheterization

Your doctor may wait to do the procedure or recommend that you do not have cardiac catheterization if you have one of the following conditions:

  • Abnormal electrolyte levels in your blood
  • Acute gastrointestinal bleeding
  • Acute kidney failure, or severe kidney disease that is not being treated with dialysis
  • Acute stroke
  • Blood that is too thin from medicines such as warfarin or other causes
  • High blood levels of a heart medicine called digoxin
  • Previous severe allergic reaction to the dye that is used during cardiac catheterization
  • Severe anemia, which is a lower-than-normal red blood cell count or hemoglobin
  • Unexplained fever
  • Untreated infection

Look for
- Cardiac Catheterization

Before Cardiac Catheterization - Cardiac Catheterization

Before cardiac catheterization, you will meet with your cardiologist, a doctor who specializes in the heart. The doctor will ask you about your medical history, including what medicines you are taking and any allergies you may have, and do a physical exam. Your doctor will also give you instructions on how to prepare for the procedure.

Diagnostic tests and procedures
- Cardiac Catheterization

You may have some of the following tests before your catheterization procedure:

  • Electrocardiogram (ECG or EKG) to look at your heart’s rhythm and other electrical activity of your heart. It can show arrhythmias, heart attacks, and other problems with the heart.
  • Chest X-ray to look at your lungs, your heart, your major blood vessels, and other structures in the chest.
  • Echocardiogram (echo) to look at the structure and function of your heart.
  • Stress test to look at how well your heart works during physical stress. The stress may be physical exercise such as walking on a treadmill, or it may be a medicine given to have the same effect.
  • Cardiac CT scan to look for narrowing of your heart’s blood vessels, and problems with the heart, larger blood vessels, and heart valves. These pictures also may help your doctor plan for procedures to open the coronary arteries.
  • Cardiac MRI to provide information on the structure and function of your heart, as well as the type and severity of heart disease.
  • Blood tests, including a complete blood count (CBC), to check your hemoglobin and platelet levels; blood chemistry tests to check how well your liver and kidneys are working; and tests to check your blood’s ability to clot.

Preparing for the procedure
- Cardiac Catheterization

Talk to your doctor about your medical history, including any medicines you take, other surgical procedures you have had, and any medical conditions you have, such as diabetes or kidney disease.

Your doctor will talk to you about how to prepare for the procedure, including:

  • When to arrive at the hospital and where to go
  • When you should stop eating or drinking
  • If and when you should start or stop taking medicines
  • How long you should expect to stay
  • What happens during the procedure
  • What to expect after the procedure, including potential complications, such as bleeding or soreness
  • Instructions to follow after the procedure, including what medicines to take

During Cardiac Catheterization - Cardiac Catheterization

Cardiac catheterization takes place in a catheterization laboratory, or cath lab, which is similar to a small operating room. The procedure is often done in a hospital, but you may be able to have the procedure in a catheterization laboratory located in a medical clinic, depending on the reason you are having the procedure and the risk for complications.

How is cardiac catheterization done?
- Cardiac Catheterization

Before cardiac catheterization, an intravenous line (IV) will be placed in a vein in your arm. Through this IV you will get a medicine to either help you relax or make you sleep during the procedure.

You will get numbing medicine, or local anesthesia, at the site where the doctor will insert the catheter. This site is called the access site and may be in the upper thigh, arm, neck, or under the collarbone. The doctor places a needle into a blood vessel at the access site. A guidewire is inserted into the needle, and the needle is taken out. Then the doctor places a small tube called a sheath in the blood vessel around the guidewire. The guidewire is removed. The catheter is then inserted through the sheath. Your doctor watches X-ray images to see where to place the tip of the catheter.

Once the catheter is in place, your doctor may use it to perform tests or treatments on your heart. For example, he or she may inject a dye into the catheter to look at blood flow in the heart. The dye will enter your blood vessels and make your coronary arteries visible in X-ray pictures.

Illustration of the cardiac catheterization process.
Cardiac catheterization. This image shows how a catheter is inserted into the femoral artery at the left upper thigh. Local anesthetic is given at the access site, and a needle is placed in the femoral artery. A guidewire is inserted into the needle, and the needle is removed. A tube called a sheath is placed around the guidewire. The guidewire is removed, and a catheter is inserted into the sheath and passed up through a coronary artery to the heart. Medical Illustration Copyright © 2019 Nucleus Medical Media, All rights reserved.


Possible risks and complications
- Cardiac Catheterization

Cardiac catheterization is a relatively safe procedure, and complications are rare. Possible complications include the following:

  • Allergic reaction to the dye used. This reaction may be hives or a more serious reaction.
  • Arrhythmias
  • Bleeding at the access site or inside your abdomen
  • blood clots formation at the access site, inside your abdomen, in a blood vessel, or in your heart
  • Collapsed lung, called pneumothorax, resulting in air in the space between your lung and chest wall
  • Damage to blood vessels, heart valves, or your heart
  • Heart attack
  • Hypothermia, especially in small children
  • Infection
  • Low blood pressure from bleeding or as a reaction to the procedure
  • Need for blood transfusion
  • Need for emergency surgery to repair a tear in the aorta or coronary artery and restore blood flow to the heart. This may be done using a coronary artery bypass graft (CABG).
  • Side effects of general anesthesia, if used. These can include nausea, vomiting, confusion, or an allergic reaction.
  • Stroke

Although not an immediate risk, repeated radiation exposure from X-rays used to place the catheter in the heart, especially with children, may increase the risk of cancer and leukemia, damage to skin, and cataracts later in life.

- Cardiac Catheterization

After Cardiac Catheterization - Cardiac Catheterization

After the procedure, your doctor will remove the catheters, sheath, and guidewire. A dressing, accompanied by pressure, is applied to the site where the catheter was inserted to stop the bleeding. The pressure may be held by hand or with a sandbag or other device. You will be moved to a recovery room, where you will lie in bed. Your heartbeat and blood pressure will be monitored.

Depending on your health before the cardiac catheterization and what additional procedures were done during the cardiac catheterization, you may have to spend the night in the hospital. You should follow your doctor’s instructions on what medicines to take and when to resume activity.

Read Life After for more information about going home after cardiac catheterization.

Life After - Cardiac Catheterization

If you have had cardiac catheterization, it is important that you receive follow-up care, know about the possible complications that may occur after the procedure, and follow the treatment plan that your doctor recommends for your condition.

Receive follow-up care
- Cardiac Catheterization

It is important to get routine follow-up care after you have cardiac catheterization. Talk with your doctor about how often you should schedule office visits.

  • Adopt a heart-healthy lifestyle, especially if your cardiac catheterization was needed because of ischemic heart disease or heart attack.
  • Follow any instructions for when to resume physical activity and lifting and at what levels.
  • Follow instructions on how to care for the site where the doctor accessed your blood vessel, including when you can take a bath or swim.
  • Keep any follow-up appointments or tests.
  • Take any medicines as directed by your doctor.
  • Talk to your doctor about any blood tests you may need if you were placed on blood thinners after your procedure.

Learn the warning signs of complications and have a plan
- Cardiac Catheterization

Complications from cardiac catheterization are rare but can be serious. A small bruise and tenderness at the access site is normal. Call your doctor immediately if you experience any of the following, as they may be signs of serious complications.

  • Bleeding from the access site that cannot be stopped with firm pressure
  • Chest pain or shortness of breath
  • Dizziness
  • Fever
  • Increased pain, redness, or bruising at the access site
  • Irregular, very slow, or fast heartbeat
  • Swelling at the access site
  • Yellow or green discharge draining from the access site
  • Your leg or arm that was used for access becoming numb or weak or any part of it turning cold or blue

Other serious complications after catheterization, although rare, include heart attack and stroke. If you think that you are or someone else is having the following symptoms, call 9-1-1 immediately.

Heart attack signs and symptoms include:

  • Chest pain or discomfort in the center of the chest or upper abdomen that lasts for more than a few minutes or goes away and comes back. It can feel like pressure, squeezing, fullness, heartburn, or indigestion.
  • Nausea, vomiting, light-headedness or fainting, or breaking out in a cold sweat. These symptoms of a heart attack are more common in women.
  • Shortness of breath, which may occur with or before chest discomfort.
  • Upper body discomfort in one or both arms or the back, neck, jaw, or upper part of the stomach.

If you think someone may be having a stroke, act F.A.S.T. and perform the following simple test.

  • F—Face: Ask the person to smile. Does one side of the face droop?
  • A—Arms: Ask the person to raise both arms. Does one arm drift downward?
  • S—Speech: Ask the person to repeat a simple phrase. Is their speech slurred or strange?
  • T—Time: If you observe any of these signs, call for help immediately. Early treatment is essential.

Read more about the signs and symptoms of a stroke.

Research for Your Health

The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the Nation’s biomedical research agency that makes important scientific discoveries to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders with treatment methods like cardiac catheterization. Learn about current and future NHLBI efforts to improve health through research and scientific discovery.

Improving health with current research
- Cardiac Catheterization

Learn about the following ways in which the NHLBI continues to translate current research into improved health for people who need procedures such as cardiac catheterization. Research on this topic is part of the NHLBI’s broader commitment to advancing heart and vascular disease scientific discovery.

  • NHLBI-Funded Study Shows Cardiac Bypass Surgery Better than Percutaneous Coronary Intervention (PCI) in Adults with Diabetes and Coronary Heart Disease. The Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) study involved 140 international centers and 1,900 adults enrolled from 2005 to 2010. This NHLBI-funded study found that adults with diabetes and coronary heart disease who underwent coronary artery bypass graft (CABG) surgery had fewer adverse events and better survival than those who underwent PCI with stent placement. Visit Cardiac bypass surgery superior to non-surgical procedure for adults with diabetes and heart disease for more information.
  • NHLBI-Funded Study Shows Older Adults with Coronary Heart Disease Have Better Survival with Cardiac Bypass Surgery than Percutaneous Coronary Intervention (PCI). This landmark study used data from 644 U.S. hospitals and looked at almost 190,000 older adults who underwent either coronary artery bypass graft (CABG) surgery or PCI. The study found that those who had undergone CABG had better survival at four years than those who had undergone PCI. Visit NIH study shows survival advantage for bypass surgery compared with non-surgical procedure for more information.
  • NHLBI Investigators Develop a New Method for Cardiac Catheterization. NHLBI researchers developed a technique that uses magnetic resonance imaging (MRI) to guide catheter placement in the heart. This could provide an alternative to X-ray imaging, which is a source of radiation. Another disadvantage of X-ray imaging is that the heart and other soft tissues can appear blurred on X-ray images. A pilot study showed that the MRI technique was as safe as the X-ray procedure and faster for navigating certain pulmonary arteries, which connect the heart to the lungs. Visit NIH pilot study shows feasibility of MRI to guide heart catheter procedures for more information.
  • NHLBI Researchers Developed a New Method for Transcatheter Aortic Valve Replacement (TAVR). TAVR is a procedure that is widely used to treat stenosis of the heart’s aortic valve. Using a catheter, doctors replace a faulty heart valve with a heart valve made from animal tissue. NHLBI investigators developed a new method, called transcaval access, that may make this procedure possible for patients who could not have undergone it in the past. See New method for performing aortic valve replacement proves successful in high risk patients for more information.

Learn about exciting ways the NHLBI has contributed to advances in cardiac catheterization.

Advancing research for improved health
- Cardiac Catheterization

In support of our mission, we are committed to advancing research on cardiac catheterization in part through the following ways.

  • We perform research. Our Division of Intramural Research, which includes investigators from the Cardiovascular Branch and its Laboratory of Cardiovascular Intervention, is actively engaged in the study of new methods and treatments using cardiac catheterization, including new methods of transcatheter aortic valve replacement (TAVR).
  • We fund research. The research we fund today will help improve our future health. Our Division of Cardiovascular Sciences oversees the Atherothrombosis and Coronary Artery Disease Branch, which supports the development of innovative technologies to diagnose and prevent coronary heart disease, atherosclerosis, and associated conditions. Search the NIH RePORTer to learn about research that the NHLBI is funding on cardiac catheterization.
  • We stimulate high-impact research. Our Trans-Omics for Precision Medicine (TOPMed) program now includes participants with atherosclerosis and coronary artery disease, which may help us understand how genes contribute to differences in disease severity and how cardiac catheterization might best be used to diagnose and manage these conditions. The NHLBI Strategic Vision highlights ways in which we may support research over the next decade, including new efforts in the field of cardiac catheterization and percutaneous coronary interventions.

Learn about exciting research areas the NHLBI is exploring that involve cardiac catheterization.

Participate in NHLBI Clinical Trials

We lead or sponsor studies relevant to cardiac catheterization. See whether you or someone you know is eligible to participate in our clinical trials.

Are you an adult interested in new technologies to study pulmonary hypertension?

This study is looking at new technologies that make it possible to study similarities and differences in genetic, molecular, and cellular processes of many diseases that are associated with pulmonary hypertension. To participate in this study, you must be at least 18 years old, be referred for right heart catheterization, and have or be at risk for pulmonary hypertension. This study is located at multiple sites across the United States, including Arizona, Maryland, Massachusetts, Minnesota, New York, and Tennessee.

Has your doctor recommended right heart cardiac catheterization for you?

This study is investigating new magnetic resonance imaging (MRI) techniques that use a guidewire to help position a heart catheter within the heart. MRI fluoroscopy shows pictures of the heart so that doctors can watch while they work. Using the guidewire during MRI may improve the procedure of heart catheterization. To participate in this study, you must be at least 18 years old, and your doctor must have recommended right heart catheterization for you. This study is located in Bethesda, Maryland.

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