Cardiac catheterization is a medical procedure that cardiologists, or heart specialists, use to evaluate heart function and diagnose cardiovascular conditions.

During cardiac catheterization, a long narrow tube called a catheter is inserted into an artery or vein in your groin, neck, or arm. This catheter is threaded through your blood vessel until it reaches your heart. Once the catheter is in place, your doctor can use it to run diagnostic tests. For example, a dye can be injected through the catheter that allows your doctor to look at the vessels and chambers of the heart with the use of a special X-ray machine.

Cardiac catheterization is performed in a hospital by a cardiologist and a team of doctors, nurses, technicians, and other medical professionals.

Your doctor may ask you to undergo cardiac catheterization to diagnose a heart problem or to determine a potential cause of chest pain.

During the procedure, your doctor can:

  • confirm the presence of a congenital heart defect (a defect present at birth)
  • check for narrow or blocked blood vessels that could cause chest pain
  • look for problems with your heart’s valves
  • measure the amount of oxygen in your heart (hemodynamic assessment)
  • measure the pressure inside your heart
  • perform a tissue biopsy from your heart
  • evaluate and determine the need for further treatment

Your doctor will let you know if you can eat or drink before the procedure. In most cases, you won’t be able to have any food or drink starting at midnight the day of your procedure. Having food and liquid in your stomach during the procedure can increase your risk of complications. You might need to reschedule if you weren’t able to fast. Also, ask your doctor before taking any medications before the procedure.

Before the catheterization begins, you’ll be asked to undress and put on a hospital gown. You’ll then lie down and a nurse will begin an intravenous (IV) line. The IV, which is usually placed in your arm or hand, will deliver medication and fluids to you before, during, and after the procedure.

A nurse may need to shave the hair from around the catheter insertion site. You may also receive an injection of an anesthetic to help numb the area before the catheter is inserted.

The catheter is guided by a short, hollow, plastic cover called a sheath. Once a catheter is in place, your doctor will proceed with the tests needed to diagnose your condition.

Depending on what they’re looking for, your doctor may perform one of the following procedures:

  • Coronary angiogram. In this procedure, a contrast material or dye is injected through the catheter.Your doctor will use an X-ray machine to watch the dye as it travels through your arteries, heart’s chambers, valves, and vessels to check for blockages or narrowing in your arteries.
  • Heart biopsy. In this procedure, your doctor will take a sample of heart tissue (biopsy) for further testing.

Your doctor may perform an additional procedure if they discover a potentially life-threatening problem during the catheterization. These procedures include:

  • Ablation. This procedure corrects heart arrhythmia (irregular heartbeat). Doctors use energy in the form of heat (radio-frequency energy) or cold (nitrous oxide or laser) to destroy heart tissue and stop the irregular heart rhythm.
  • Angioplasty. During this procedure, doctors insert a tiny inflatable balloon into the artery. The balloon is then expanded to help widen a narrowed or blocked artery. Angioplasty may be combined with a stentplacement — a small metal coil that is placed in the blocked or clogged artery to help prevent any future narrowing problems.
  • Balloon valvuloplasty. In this procedure, doctors inflate a balloon-tipped catheter into narrowed heart valves to help open the restricted space.
  • Thrombectomy (blood clot treatment). Doctors use a catheter in this procedure to remove blood clots that could potentially dislodge and travel to organs or tissue.

You’ll be sedated during a catheterization, but you’ll remain alert enough to respond to instructions from doctors and nurses.

During the catheterization, you may be asked to:

  • hold your breath
  • take deep breaths
  • cough
  • place your arms at various positions

This will help your healthcare team get a better image of your heart and arteries.

Cardiac catheterization can help your doctor diagnose and treat problems that might otherwise cause larger issues, such as a heart attack or stroke. You may be able to prevent a heart attack or stop a future stroke if your doctor is able to correct any problems discovered during the procedure.

Any procedure that involves your heart comes with a particular set of risks. Cardiac catheterization is considered relatively low risk, and very few people have any problems. The risks of complications, though rare, are higher if you have diabetes or kidney disease, or if you’re 75 years or older.

The risks associated with catheterization include:

  • an allergic reaction to the contrast material or medications used during the procedure
  • bleeding, infection, and bruising at the catheter insertion site
  • blood clots, which may trigger a heart attack, stroke, or another serious problem
  • damage to the artery where the catheter was inserted, or damage to the arteries as the catheter travels through your body
  • irregular heart rhythm (arrhythmias)
  • kidney damage caused by the contrast material
  • low blood pressure
  • torn heart tissue

Cardiac catheterization is a generally quick procedure and usually lasts less than an hour. Even though it’s performed rather quickly, you’ll still need several hours to recover.

Once the procedure is finished, you’ll be taken to a recovery room where you’ll rest while the sedative wears off. The catheter insertion site may be closed with a suture or a “plug” made of material that works with your body to create a natural clot in the artery.

Resting after the procedure will prevent serious bleeding and allow the blood vessel to heal completely. You will likely go home the same day. If you’re already a patient in the hospital and receive a catheterization as part of your diagnosis phase or treatment, you’ll be brought back into your room to recover.

Longer stays are usually required if you have an additional procedure, such as angioplasty or ablation, during the catheterization.

Your doctor should be able to discuss the results of your catheterization soon after the procedure is completed. If you had a biopsy, the results may take a while. Depending on the findings, your doctor will recommend future treatment or procedures.