Patient Basics: Cardiac Catheterization

Cardiac catheterization (heart cath) is a procedure in which a doctor guides a thin, flexible tube (catheter) through a blood vessel in your wrist or groin up to your heart. It shows whether the heart’s arteries are narrowed or blocked, and it can measure pressures inside the heart. If the doctor finds a blockage, they can often open it during the same procedure. You stay awake but relaxed, and many people go home the same day.

Key points

• The most common reason for a heart catheterization is to look for blocked heart (coronary) arteries.
• The catheter usually goes in through an artery in the wrist. The groin is used when needed.
• A blocked artery can often be opened right away with a tiny balloon and a mesh tube (stent).
• Serious problems are uncommon. Bruising where the catheter went in is the most common side effect.
• Press on the site and call 911 if it bleeds and won’t stop.

Types of heart catheterization

• Left heart catheterization. The catheter travels through an artery to the left side of the heart. The doctor injects dye into the coronary arteries and takes X-ray pictures. This picture is called a coronary angiogram.
• Right heart catheterization. The catheter goes through a vein in the neck, arm or groin to the right side of the heart and the arteries of the lungs. It measures pressures and how much blood the heart pumps. It helps with heart failure, high blood pressure in the lungs and planning for a heart transplant.
• Right and left (double) heart catheterization. Both are done in one visit.

Why you might need a cardiac catheterization

• Chest pain or a stress test that suggests narrowed heart arteries
• A heart attack, when the goal is to open the blocked artery as fast as possible
• Heart failure or a weak heart muscle without a clear cause
• A heart valve problem, or planning for valve surgery
• High blood pressure in the lungs (pulmonary hypertension)
• A heart defect present from birth

Getting ready

• Tell your care team if you have had a reaction to X-ray dye, if you have kidney disease or diabetes, or if you could be pregnant.
• Review your medicines. You may need to pause blood thinners such as warfarin or apixaban, or change your diabetes medicine. Don’t stop aspirin or other heart medicines unless you are told to.
• Food and drink. You will be told when to stop eating and drinking, often about 6 hours before.
• Tests. You will likely have blood tests to check your kidneys and blood clotting, and an electrocardiogram (ECG).
• Plan a ride. You can’t drive yourself home.

During the procedure

The procedure takes place in a room called a cath lab. You lie on a narrow table under a large X-ray camera, with patches on your chest to track your heartbeat. A nurse gives you medicine through an IV to help you relax. Most people stay awake and can talk.

The doctor numbs a small spot on your wrist or groin and places a short plastic tube (sheath) in the blood vessel. The catheter passes through the sheath and up to the heart, guided by X-ray. You may feel pressure, but you won’t feel the catheter moving, because the inside of blood vessels has no nerves that sense it.

The doctor then injects dye and takes pictures. The dye can cause a warm, flushing feeling for a few seconds. Some people briefly feel as if they need to urinate. Tell the team if you have chest pain or trouble breathing.

If an artery is badly narrowed, the doctor may treat it right away. This is called angioplasty or PCI. A balloon at the tip of a catheter widens the artery, and a stent is left in place to keep it open. A test-only heart cath often takes 30 to 60 minutes. Placing stents takes longer.

After a heart cath

The sheath comes out at the end. At the wrist, a tight band presses on the artery for a couple of hours. At the groin, a nurse presses on the site or the doctor uses a small plug to seal it, and you lie flat for a few hours. Drink plenty of fluids to help flush out the dye.

Many people go home the same day, especially after a test-only cath through the wrist. After a stent or a groin approach, some stay one night. At home:

• Expect a bruise or a small, firm lump at the site for a week or two.
• Don’t lift anything heavy, or push hard with that arm, for several days. For a groin site, avoid heavy lifting for about a week.
• Shower, but skip baths, hot tubs and swimming until the site has healed, usually about a week.
• Ask when you can drive and go back to work. For most people it is within a few days.

If you got a stent, you will take two medicines that stop blood clots, usually aspirin plus clopidogrel, ticagrelor or prasugrel. Stopping them early can cause a clot in the stent. Never stop them without talking to your cardiologist.

Possible risks of cardiac catheterization

Most people have no problems. Serious ones, such as a stroke, heart attack or damage to an artery, happen in fewer than 1 in 100 people. Possible problems include:

• Bleeding or a large bruise at the site
• An allergic reaction to the dye
• Kidney strain from the dye, mostly in people who already have kidney disease or diabetes
• An irregular heartbeat during the procedure, which usually stops on its own
• Infection at the site

The X-ray dose is small, but tell the team if you are pregnant.

Your results

The doctor often shares the main findings right after the procedure. They may describe a narrowing as a percentage, such as “70% blocked.” Depending on what they find, the plan may be medicines alone, a stent, heart bypass surgery, or treatment for a valve or heart failure.

When to call your doctor

• The site swells, gets more painful, or forms a growing lump
• The site turns red, warm or leaks pus, or you have a fever
• Your hand or leg on that side feels cold, numb, or looks pale or blue

Call 911 if you have chest pain, trouble breathing, or bleeding that doesn’t stop after 10 minutes of firm pressure.

Common questions about cardiac catheterization

Is a heart catheterization considered surgery?

No. A heart cath is a procedure done through a small needle puncture, not an open operation. You stay awake with medicine to relax you, and no stitches are usually needed. If the results show you need bypass surgery, that is a separate operation on another day.

How long does it take for the artery to heal after a heart cath?

The puncture seals within hours, but the artery takes about a week to heal fully. That is why you should avoid heavy lifting and soaking in water for several days. The bruise can take two weeks or more to fade.

Can you have a heart catheterization without a hospital stay?

Yes, often. Many test-only caths are done as an outpatient procedure, and you go home the same day after a few hours of rest. People who get a stent, have a groin approach or have other health problems may stay overnight.

Questions to ask your doctor

• Why do I need a heart cath, and are there other tests I could have instead?
• Will you go in through my wrist or my groin?
• Which of my medicines should I stop or change beforehand?
• If you find a blockage, will you treat it during the same procedure?
• When can I drive, work and exercise again?

Learn more

• Cardiac catheterization (National Heart, Lung, and Blood Institute)
• Cardiac catheterization (MedlinePlus, U.S. National Library of Medicine)

This guide is general information and doesn’t replace advice from your own doctor. Last updated October 2026.