Basic Facts:

  • Cardiac catheterization and angiography are combined for a diagnostic test that evaluates blood flow in the coronary arteries. These are the vessels on the surface of the heart that feed blood to the heart muscle to allow it to pump properly. 
  • Cardiac catheterization involves the insertion of a very thin tube called a catheter into an artery in the leg or arm. The catheter is threaded to the arteries in the heart. A physician injects contrast dye through the arteries and takes pictures with an x-ray machine to get a 'road map' of the heart's blood vessels. Those pictures, along with blood pressure measurements inside the heart, help doctors pinpoint the location and extent of problems with the heart's blood supply and decide on treatment.
  • This diagnostic procedure may be used with a therapeutic procedure, such as angioplasty and stenting, which is designed to open a narrowed or blocked artery.
Cardiac Catherization


As people age, the normal flow of blood through the arteries can be affected by the buildup of cholesterol and fat (plaque) on the artery walls. Over time, plaque continues to grow and causes the arteries to become narrowed, reducing blood flow to the heart. This condition is called atherosclerosis, which may begin as early as childhood.

To find out the extent of blockage in the coronary arteries, doctors use cardiac catheterization to collect information about the heart’s blood supply. The procedure is also used to measure pressures inside the heart and lungs, or to assess or treat other cardiac problems such as cardiac valve disease.

A cardiac catheterization sometimes leads to the need for a percutaneous coronary intervention.


Pre-Test Guidelines 

Prior to the procedure, the patient should:

  • Inform their physician of medications to control diabetes, hypertension, high cholesterol or angina, and
  • Notify their physician of any iodine contrast allergies,

People who are allergic to iodine, or people with diabetes or kidney problems, may have an increased risk of an allergic reaction to the iodine in the contrast dye and should notify the physician of their allergy before the test. The physician can administer allergy medications before the test to prevent any symptoms.

Additional specific instructions will be provided prior to testing.


Other than a sedative, people having a cardiac catheterization might not receive any other drugs because some anesthetics can alter how the heart functions. Catheterized patients also need to remain partially alert so they can describe sensations to the physician performing the test and report any chest pain. The test is otherwise generally painless.

Cardiac catheterizations are typically performed with the person being tested lying flat on a table with an x-ray machine above or on the side of the table. The site on the leg or arm where the catheters will be inserted is cleaned and any hair around the insertion point is shaved. This helps minimize the risk of infection. The insertion point is numbed with a local anesthetic, and doctors make a tiny puncture in the skin to access the artery.

Once the puncture has been made, a guide wire is inserted into the artery. A catheter sheath, a short, hollow tube, is then guided over the wire. When the catheters are inserted, most people feel only a slight pressure or a sensation of mild tugging. Because there are no nerve endings inside the arteries, people being catheterized cannot feel the catheters as they move through the body. Using special x-ray technology, the doctors then guide the catheters through the arterial system to the area of the heart that is being studied.

After taking pressure measurements inside the heart, contrast dye is injected through the catheter and will flow into the coronary arteries. Many people who have undergone an angiography report feeling sensitive to their heartbeats and a warm, flushing sensation when the dye is injected, a normal reaction that lasts for 20 to 30 seconds. The dye flows through the heart’s arterial system, and the physician traces its flow with an x-ray machine to get pictures of the heart’s blood vessels. More than one injection of dye will be used during the procedure.  

When the procedure is completed, the catheter is removed through the sheath at the insertion site. Sometimes, the sheath stays in the artery for a short time and is covered with a small dressing. 

When the sheath is removed, pressure may be applied on the insertion site for 15 to 30 minutes to allow the puncture area to close and prevent bleeding. When the femoral artery in the groin is used as the access point, the patient may have to rest in bed with the leg held straight for one to four hours. Other techniques that may be used to close the puncture site include a cork-like device inserted into the wound to seal the area or a stitching device with sutures that close the incision and eventually dissolve. 

Cardiac catheterization usually takes between 45 minutes and three hours to complete.

Post-Test Guidelines

Most people can resume normal activities within a few days to a week after their catheterization if no complications result from the procedure. Some guidelines to follow after a cardiac catheterization may include:

  • Avoid lifting more than five or 10 pounds for the first few days,
  • Avoid baths for a few days (showers are usually permitted within 24 hours), and
  • Sexual activity can usually be resumed within three to five days.