Cardiac catheterization

Cardiac catheterization is a common, relatively painless, nonsurgical procedure that can help your doctor diagnose a heart problem. In some cases, catheterization can be used to treat heart disease as well. To perform the procedure, your cardiologist inserts a long, flexible tube called a catheter into a blood vessel and gently guides it toward your heart. Once the catheter is in place, X-rays and other tests are done to help your doctor evaluate how well your heart is working.

Read on to learn more about cardiac catheterization, who needs it and a brief tutorial about how your heart functions.

Why do you need a cardiac catheterization?

Simply put, most cardiac catheterizations are prompted by a patient’s symptoms. If you have had shortness of breath, pain or discomfort in the chest, arm or jaw, dizziness, palpitations or any other symptoms of heart trouble, you are a candidate for the procedure. Or, your doctor may have found signs of heart problems during a physical exam. Before cardiac catheterization, most patients have probably undergone a number of tests, such as an echocardiogram, a treadmill test and perhaps a nuclear scan. The next step may be cardiac catheterization, which can help your doctor more precisely identify a heart problem.

Cardiac catheterization can show:

  • If the blood vessels in your heart are clogged.
  • If your heart is pumping normally and blood is flowing correctly.
  • If you were born with any heart problems.

What conditions should you alert your doctor about before cardiac catheterization?

Tell your doctor before undergoing cardiac catheterization if you are pregnant. The procedure will probably be postponed until after your baby is born. Those who have had allergic reactions to iodine-containing X-ray contrast liquid or shellfish also should alert their physician. Those conditions may require medication before the procedure to prevent an allergic reaction during catheterization. 

How does a healthy heart work?

To understand why cardiac catheterization may be needed to help diagnose a heart problem, you first need to know how a healthy heart works. Your heart pumps blood throughout your body. The coronary arteries supply the oxygen-rich blood your heart needs, while the heart’s chambers and valves keep blood flowing in the proper direction. Let’s break that down into more detail. 

Coronary arteries: Supplying oxygen to your heart

To do its work, your heart needs a constant supply of oxygen. The coronary arteries are blood vessels that wrap around the surface of your heart and keep it supplied with oxygen-rich blood.

The left main coronary artery splits into two branches:

  • The circumflex and the left anterior descending arteries, which supply blood to the front, left side and back of the heart.

The right coronary artery supplies blood to the bottom, right side and back of the heart.

Inside your heart

Your heart is made up of two sides, four chambers and four valves. The chambers and valves keep blood moving in the proper direction through the heart, and then out to the lungs and the rest of the body. Let’s take a closer look at each component of the heart.

The two sides of the heart

The right side of your heart pumps blood through your lungs, where it receives oxygen. The left side pumps the oxygen-rich blood throughout your entire body.

The four chambers

The heart has four compartments, known as chambers: The right atrium, right ventricle, left atrium, and left ventricle. Each chamber holds blood as it flows through the heart. The right and left atria pump blood into the right and left ventricles. The ventricles then pump blood away from the heart.

The four valves

The four valves act like one-way doors that keep blood moving forward through the heart’s chambers. When your heart beats, the valves open to let blood through. The valves then close after each beat in order to keep blood from flowing backward.

Diagnosing heart problems

Cardiac catheterization can be used to help identify artery, valve or muscle problems. Your doctor uses the information gained during cardiac catheterization to decide if you need treatment and to plan the best course of action. Some of the conditions cardiac catheterization can diagnose include: 

Coronary artery disease

Cardiac catheterization can show whether you have coronary artery disease. This condition is caused by atherosclerosis, otherwise known as hardening of the arteries. Atherosclerosis occurs when a fatty material called plaque builds up in the lining of the artery and reduces blood flow to the heart. As plaque build-up increases, your artery has difficulty supplying enough oxygen-rich blood to your heart, especially when it needs it most, such as during exercise. Terms you might hear to describe the condition of your arteries include:

  • A healthy artery is one that allows the easy flow of blood and oxygen to the heart muscle.
  • A damaged artery is one where blood flow to the heart muscle is reduced, usually by the build-up of plaque. If there is little blockage, you probably won’t feel any symptoms.
  • A narrowed artery means that blood flow to the heart muscle is partially blocked. As a result, many patients experience the chest discomfort known as angina.
  • A blocked artery is dangerous. The blockage is caused by plaque build-up or a blood clot and may result in a heart attack.

Heart valve problems

Problems can occur if a heart valve doesn’t open or shut completely. Cardiac catheterization can help your doctor take a closer look at your heart’s valves to find out if they’re working properly.

Normal valve

With each beat of the heart, the valve opens to let blood into the next chamber. When the beat ends, the valve shuts to keep blood from flowing backward.

Abnormal valve

If a valve doesn’t open or shut completely, blood can build up or flow backward into the chamber it just left. The heart must then work harder to pump out the extra blood. The sound of blood flowing through an abnormal valve is called a heart murmur. It can be heard through a stethoscope. 

Heart muscle or structural problems

Some people are born with problems in their heart structure or holes in the walls that separate the heart’s right and left chambers. This can cause blood to flow in the wrong direction. Other heart muscle problems develop later in life. Cardiac catheterization can help detect these problems.

Tests for diagnosing heart problems

To determine if you have a heart problem, several tests may be performed during cardiac catheterization. These tests create pictures of your heart and measure your heart’s blood flow and pressure. The test results give your doctor detailed information about your heart’s condition. If a problem exists, this information can help you and your doctor decide on the best treatment for you.

Coronary angiography

Angiography is a special type of X-ray that allows an artery blockage to be viewed and recorded on film. Ventriculography is a similar type of X-ray that allows the heart’s chambers and pumping action to be viewed and recorded on videotape. Angiography and ventriculography can reveal abnormal movements of the heart’s wall due to coronary artery disease or other conditions. These tests can also detect abnormal valves, artery blockages and holes between the heart’s right and left sides.

Other tests

During cardiac catheterization, your doctor may perform other tests. Some of these tests measure the amount of blood your heart pumps to see if it is less than normal. Other tests measure blood pressure in the heart chambers. They are designed to find out if blood is flowing properly through your valves and if the heart muscle is pumping as it should.

Treating Heart Problems

Cardiac catheterization may also be used to treat certain heart problems. Because the catheter can go inside the heart and coronary arteries without surgery, it may be used to administer nonsurgical treatments that can treat blood clots and coronary artery disease. Cardiac catheterization treatments include:


Angioplasty opens clogged arteries by compressing fatty build-up against the artery wall. A catheter with a small balloon at the end is inserted into the artery and moved to where the artery is clogged. The balloon is inflated and deflated several times to compress the fatty material, open the artery, and increase blood flow. Then the catheter is removed.

Other treatments

Other treatments for coronary artery disease that can be done using cardiac catheterization are:

  • Artherectomy removes plaque from artery walls using a special catheter.
  • Laser catheters can clear blockages inside artery walls.
  • Stents are metal devices that are placed permanently inside arteries to help keep them open.
  • Medications can be delivered through a catheter to the site of a blood clot in an artery in order to dissolve it.

Preparing for your catheterization

Before your cardiac catheterization, your doctor will explain the possible risks and benefits of the procedure. You’ll also receive complete instructions on what to expect and what you need to do to be prepared for the procedure. You can help prevent complications by following all of your doctor’s instructions carefully. Don’t hesitate to ask any questions you may have.

Understanding the risks

The risks of cardiac catheterization are fairly low and are usually outweighed by the benefit of knowing the exact condition of your heart. Your doctor will discuss any potential risks and side effects with you. Then you’ll be asked to sign a legal consent form. This gives your doctor permission to perform the procedure. Possible risks include:

  • Bleeding or clotting
  • Perforation of the heart muscle or blood vessel
  • Arrhythmia (abnormal heartbeat)
  • Allergic reaction to X-ray sensitive liquid
  • Heart attack or stroke

Before your procedure

The night before your catheterization, you may be asked not to eat or drink anything after midnight. You’ll probably be admitted to the hospital on the day of the procedure. Before catheterization begins, you may be given medication to help you relax. The skin where the catheter will be inserted may be shaved. Then you’ll be taken to the catheterization laboratory.

In the catheterization lab

The laboratory may feel cool, but you’ll be covered with sterile drapes. The nurse can also bring you a blanket. Only the patch of skin where the catheter will be inserted is exposed. The doctor, nurses and technicians wear sterile gowns, gloves and possibly masks. It may take half an hour for the catheterization lab team to finish preparations for the procedure once you arrive.

During the procedure

Cardiac catheterization usually takes an hour or less. The area where the catheter is inserted is numbed with a local anesthetic. You remain awake during the procedure because your cooperation is needed from time to time.

Inserting the catheter

A local anesthetic is administered by injection, so you won’t feel pain at the insertion site. The most common insertion site is a blood vessel in your groin or arm. The injection feels like a bee sting and is generally the most uncomfortable part of the procedure.

Before the catheter is injected, what’s known as an introducing sheath is inserted into a blood vessel. You may feel a little pressure when it is inserted, but this sensation should pass quickly.

The diagnostic catheter is then inserted through the introducing sheath. While watching the catheter’s progress on an X-ray video monitor, your doctor gently guides it toward the heart. You should feel no pain as the catheter moves through your body and into your heart.

Performing tests

To conduct different tests in your heart and coronary arteries, your doctor inserts new catheters or changes the position of the catheter or X-ray equipment. During angiography and ventriculography, X-ray contrast fluid is injected into your blood vessels or heart chamber. You may be asked to hold your breath, and you may feel a hot flush all over your body for about 10 seconds. Your doctor will probably ask you to cough to help move the liquid through your heart.

Removing the catheter

After the tests are finished, your doctor removes the catheter and introducing sheath. If the sheath was inserted in your arm, your doctor may close up the insertion site with stitches. If it was inserted in your groin, a nurse clamps or presses down firmly on the insertion area for about 15 minutes to stop any bleeding. A sandbag or pressure bandage is then placed on the insertion site before you are returned to your room.

After your catheterization

After your catheterization, you need to remain lying down for four to six hours. If the catheter was inserted in your groin, you’ll be asked not to move your leg in order to prevent bleeding. Most people have no pain after catheterization. Many patients go home from the hospital the same day, while others stay overnight. 

Close monitoring

You’ll be watched carefully after the procedure. A nurse checks your blood pressure and the insertion site frequently to make sure there is no bleeding. Your doctor also may come in to check on you. The X-ray contrast liquid may cause you to urinate more than usual, and you may be asked to drink a lot of fluid to help flush the contrast liquid out of your system.

Tell your nurse if:

  • You feel any chest pain or discomfort at the insertion site.
  • The arm or leg used for insertion becomes numb or cold.
  • You feel warmth or wetness around the insertion site, a sign that you may be bleeding.

Finding out your results

Your doctor will discuss your test results with you. Sometimes cardiac catheterization shows that your heart is working normally. If there is a problem, your doctor will explain it to you and discuss possible treatments.

Going home

Have a family member or friend drive you home from the hospital. Most people can return to normal activities a day or two after they come home. It’s a good idea to avoid heavy lifting and only engage in light activities for a few days. You may find a small bruise or lump under your skin at the insertion site. It’s common after catheterization and will disappear within a few weeks. 

Call your doctor if:

  • The insertion site begins to bleed.
  • You feel any chest pain or discomfort at the insertion site.
  • The arm or leg where the catheter was inserted feels cold or numb.
  • The bruising or swelling increases.

Planning the next step

After your cardiac catheterization, you should be able to return to your regular daily activities. If you do have a heart problem, the detailed information gained during the catheterization procedure will help you and your doctor decide on the best possible treatment for you.