Cardiac catheterization, also known as cardiac cath or heart 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 to perform other tests or procedures.

Your healthcare provider may recommend cardiac catheterization to find out the cause of symptoms such as chest pain or irregular heartbeat. Before the procedure, you may need to 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 through the blood vessels to your heart. It may be used to examine your heart valves or take samples of blood or heart muscle. Your doctor may also use ultrasound, a test that uses sound waves to create an image, or they may 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. Problems following the procedure are rare but can include bleeding and blood clots. Your healthcare provider will monitor your condition and may recommend medicines to prevent blood clots.

Your healthcare provider may recommend cardiac catheterization to find out what is causing symptoms of a heart problem or to treat or repair a heart problem.

Cardiac catheterization can be used for different purposes.

• Give a better understanding of other test results, such as echocardiography (echo), cardiac MRI, and cardiac CT scan. This is especially helpful if the results from those tests could not identify the problem or differ from what your doctor finds when examining you.
• Diagnose heart conditions such as arrhythmia, heart attack, pulmonary hypertension, cardiomyopathy, coronary heart disease, and heart valve diseases, including aortic stenosis and mitral regurgitationexternal link .
• Evaluate you before a possible heart surgery, such as a heart transplant.
• Measure oxygen levels and blood pressure in the chambers of your heart and the pulmonary arteries.

Your doctor may do other procedures to diagnose or treat your condition during cardiac catheterization.

• Collect biopsies of small samples of heart tissue for more laboratory testing. Biopsies can be used for genetic testing, to check for myocarditis (a type of heart inflammation), or to look for transplant rejection.
• Use coronary angiography to look at the heart or blood vessels by injecting dye through the catheter.
• Perform minor heart surgery to treat congenital heart defects and replace or widen narrowed heart valves.
• Use percutaneous coronary intervention (PCI) to open narrowed or blocked areas of the coronary arteries. PCI may include balloon dilation, also known as angioplasty, or stent placement. Most people who have heart attacks or underlying heart disease have narrowed or blocked coronary arteries.
• Apply catheter ablation to treat arrythmias.

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

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

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

Diagnostic tests and procedures

You may need to have some tests before your catheterization procedure.

• An electrocardiogram (ECG or EKG) looks at your heart’s rhythm and other electrical activity. It can show arrhythmias, heart attacks, and other heart problems.
• A chest X-ray looks at your lungs, your heart, your major blood vessels, and other structures in your chest.
• An echocardiogram (echo) looks at the structure and function of your heart.
• A stress test looks 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 caused by a medicine that can be given to get the same effect.
• A cardiac CT (computed tomography) scan looks for narrowing of your heart’s blood vessels and problems with the heart, larger blood vessels, and heart valves. These pictures may also help your doctor plan for procedures to open the coronary arteries.
• Cardiac MRI (magnetic resonance imaging) provides information on the structure and function of your heart, as well as the type and severity of heart disease.
• Blood tests check for certain diseases and conditions. A complete blood count (CBC) checks your hemoglobin and platelet levels. Blood chemistry tests check how well your liver and kidneys are working. Other tests may check your blood’s ability to clot.

Preparing for the procedure

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

Your healthcare provider 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 problems, such as bleeding or soreness.
• Instructions for recovering after the procedure, including what medicines to take.

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 lab located in a medical clinic, depending on the reason for the procedure.

How is cardiac catheterization done?

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

You will get numbing medicine at the site where the doctor will insert the catheter. This may be in the upper thigh, arm, or neck or under the collarbone. The doctor will place a needle into the blood vessel. 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, your doctor 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 images.

Possible risks

Cardiac catheterization is a relatively safe procedure, and complications are rare. However, as with any procedure involving the heart and blood vessels, there are some risks.

Possible risks include the following:

• Allergic reaction to the dye
• Irregular heart rhythm (arrhythmia)
• Bleeding or discomfort where the catheter was inserted
• Blood clots
• Collapsed lung, called pneumothorax
• Damage to blood vessels, heart valves, or the heart from the catheter
• Heart attack
• Hypothermia, or very low body temperature, especially for small children
• Infection
• Low blood pressure from bleeding or as a reaction to the procedure
• Need for a blood transfusion
• Need for emergency surgery to repair a tear in a blood vessel, such as the aorta or a coronary artery, and restore blood flow to the heart. This may be done using a coronary artery bypass graft (CABG).
• Side effects of the medicine to help you relax or sleep, if used. These can include nausea, vomiting, confusion, or an allergic reaction.
• Side effects of radiation. Although not an immediate risk, repeated radiation exposure from X-rays used to place the catheter may increase the risk of cancer and leukemia, skin damage, and cataracts later in life. This is especially true for children.
• Stroke

After the procedure, your doctor will remove the catheters, sheath, and guidewire. A dressing, accompanied by pressure, will be applied to the site where the catheter was inserted to stop the bleeding. The pressure may be applied by hand or with a sandbag or other device.

You will be moved to a recovery room, where you will lie in a bed. Your healthcare provider will monitor your heartbeat and blood pressure.

Depending on your health before the cardiac catheterization and any additional procedures done during the cardiac catheterization, you may have to spend the night in the hospital. Ask your healthcare provider about what medicines to take and when to resume activity as you recover from the procedure.

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 healthcare provider recommends for your condition.

Receive follow-up care

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

• Adopt a heart-healthy lifestyle, especially if your cardiac catheterization was needed because of coronary heart disease or heart attack.
• Ask when you can resume physical activity and lifting objects, and what level of activity is best for you.
• Follow instructions on how to care for the site where the doctor accessed your blood vessel, including information about 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 healthcare provider about any blood tests you may need if you were placed on blood thinners after your procedure.

When to call the doctor

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

• 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. Know the signs of a heart attack and signs of a stroke, and call 9-1-1 immediately if you or someone else is having symptoms.