Cardiac Catheterization

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Cardiac catheterization is a diagnostic test that uses a special x-ray technique to study the heart. To begin, a long, thin tube called a catheter is inserted through a blood vessel and guided into your heart under x-ray visualization. Next, a contrast medium, commonly called "dye", is given through the catheter, which allows the physician to see the heart chambers, valves and coronary arteries on an x-ray. Heart pressures are measured and blood samples may be taken. Then, x-rays are performed that may show significant narrowing or blockage of the coronary arteries.

A cardiac catheterization is done to gather information about the coronary arteries and the structure and function of the heart. This will help the doctor form a treatment plan based on the results.

Risk Factors

Cardiac catheterization is a relatively safe procedure, however the following risks can occur:

  • Bleeding at the site where the catheter is inserted
  • Injury to the vessel in which the catheter is placed
  • Allergic reaction to the dye
  • Abnormal heartbeat
  • Kidney damage
  • Very rarely, heart attack, stroke or death may occur

What to Expect Before the Catheterization

Your physician will review the risks, benefits and alternatives to cardiac catheterization with you before the procedure takes place, and you will be asked to sign a consent form. An ECG, chest x-ray and routine blood work may be performed.

Your cardiac care nurse or cardiologist will need to know some important information about you, including:

  • Bleeding problems
  • Allergies to x-ray dye, iodine, medications or foods such as shellfish
  • Any medications you are taking including blood thinners, diabetes medication, herbs, supplements, or over the counter medications
  • If you are pregnant
  • If you cannot lay flat on your back for several hours
  • If you have kidney problems
  • If you currently have an infection
  • If you have peripheral vascular disease

How You can Prepare

  • Continue to take all your medications as prescribed by your doctor unless instructed otherwise.
  • If you take warfarin (coumadin), you will be asked to stop 5 days prior to the procedure.
  • If you are diabetic and take metformin, do not take on the morning of the procedure and for 2 days after the procedure.
  • If you are diabetic and take insulin, ask your cardiac nurse or cardiologist about changes in the dose of insulin on the day of your test.
  • If you take aspirin and/or clopidogrel, continue to take these.
  • Bring all your prescription medications with you in the original bottles.
  • Bring your health card and hospital blue card.
  • If you do not speak English, it is helpful to have an interpreter with you on the day of the test.
  • Pack something to read but leave all your valuables at home.
  • Arrange for a ride home since you should not drive yourself.
  • Plan to have someone stay with you the first night after the test.

The Day of the Procedure

  • Outpatients may have a light early breakfast (e.g. toast, juice).
  • You should avoid eating or drinking for 2 hours before the procedure.
  • Take your usual medications unless directed otherwise.
  • You may be given some sedation to help you relax prior to or during the procedure.
  • After you have been assigned to a bed and have changed into a hospital gown, an intravenous line will be placed in your arm to give medications or fluids if needed.

What to Expect During the Catheterization

Upon arrival in the cardiac catheterization suite, you will be assisted onto a special table and draped in sterile towels and sheets. It is important that you not touch the sheet or move. If you have to move, ask the nurse first.

You will be awake during the procedure, however a local anesthetic, commonly called "freezing" will be injected into the area where the catheter will be inserted. This will numb the site so that you do not feel pain.

Next, a short tube called a sheath will be inserted into the groin or arm. This may cause a feeling of pressure at the moment of insertion.

The cardiac catheter is then inserted through the sheath and into your blood vessel. An x-ray video screen shows the catheter moving toward your heart. You should not feel any pain as this takes place.

The "dye" is injected through the catheter into the heart chambers and coronary arteries. The vessels can then be seen on an x-ray picture called an angiogram. When the "dye" is given, you may feel a hot flush over your body, which should pass in about 45 seconds. You may also have a feeling that you passed urine but this is just a sensation.

The entire procedure will last about a half hour to one-and-a half hours.

What to Expect After the Catheterization

Once the procedure is finished, you will be transferred to a special recovery room. The small sheath will be removed from your arm or groin, and pressure will be applied by a clamp to stop any bleeding. The clamp will be removed once the bleeding has stopped. This will take 15-30 minutes, and you will be required to lie still and not move your arm or leg. Once the bleeding has stopped, the nurse will remove the clamp and place a small bandage over the puncture site.

You must remain in bed with your arm or leg straight for up to 2 hours following the removal of the sheath. The nurse will let you know when you can start to move around. During your bedrest do not lift your head, strain, bend the affected arm or leg or cross your ankles. If you have to cough or sneeze put pressure over the bandaid with your hand.

You may need to urinate often during the first few hours after the procedure. This is normal and is caused by the dye used during the test. You will be required to use a urinal or bedpan during this time since you must remain lying down.

Monitoring Your Condition

You may need to stay in the hospital for several hours after the procedure. During your stay, a cardiac care nurse will monitor your condition, including your pulse, blood pressure and puncture site.

Your Results

During the procedure, the cardiologist can determine the preliminary results. However, making a final diagnosis requires a complete review of the x-ray pictures and this can take several hours. Before you leave the hospital, the cardiologist will discuss the final results with you and together, you will decide on the treatment plan.

Going Home

The Day of Cardiac Catheterization

You may have a bruise at the insertion site and feel a small lump the size of an olive. These are normal and will go away on their own in a few weeks.

You will need a responsible adult to drive you home. If you live more than one hour away, you will need to stop at a rest station and walk a little every hour.

When you arrive home, avoid unnecessary walking, bending or prolonged sitting and do not physically exert yourself. You may resume your normal diet and medications unless instructed differently.

The Day After Cardiac Catheterization

Check your insertion site the next morning after the procedure for bruising, swelling or bleeding. If you have a bruise, it may change colour and extend down the limb over the next few weeks as it heals. Bruising is common. Remove the bandage, shower and gently pat the puncture site dry. Continue to keep the area clean and dry. Avoid soaking in a bath for 2 to 3 days.

You may resume your normal activities, but avoid excessive exertion for another 24 hours and any heavy lifting (over 10 lbs) for several days. You may return to work in 2 to 3 days after cardiac catheterization, unless directed otherwise by your cardiologist. You may resume sexual activity 2 to 3 days after the procedure.


You should see your family doctor within one week of returning home. You will be provided with a summary of your test results to take with you to the appointment. If any of the following occur, contact your family doctor or visit the emergency department:

  • If the affected arm or leg is painful, cold, numb, weak or blue in colour.
  • If there is increased pain and swelling at the insertion site.
  • Difficulty urinating or blood in your urine.
  • Any excessive bleeding. If a large amount of bleeding occurs apply firm pressure, call 911 then lie down.

A cardiac catheterization has been done to help diagnose a heart problem. After reviewing the results, your cardiologist may recommend further procedures. He or she will be able to tell you about your heart condition and what treatments are best for you. Treatments may include an angioplasty, which uses a balloon and stents to open up narrowed blood vessels, or bypass heart surgery, which uses a blood vessel from your chest and/or leg to go around the blocked area. Your heart problem may be controlled with medication and lifestyle changes.