X-rays can tell you a lot about problems with your bones, but when it comes to matters of the heart, they need a little help.
Cardiac catheterization is a procedure that adds an injection of special dye to x-ray imaging to allow doctors to see inside your heart and surrounding arteries. It can confirm&mdash;or exclude&mdash;a suspected problem, clarify confusing symptoms or even be used to treat a known condition. 
Like any medical procedure, it carries some risks, notes the <a href="[BASEDOMAIN]/healthinfo/bouncelink.aspx?shortcut=nih" target="_blank">National Institutes of Health</a> (NIH). Most are minimal and occur infrequently; major complications are even rarer. 
But the benefits of viewing the inner workings of the heart without resorting to major surgery can be huge. 
The procedure 
Cardiac catheterization is usually performed in the hospital, where you might be admitted either the night before or the morning of the procedure. 
Equipment used in the procedure includes:
<ul>
 <li>An intravenous (IV) line. </li>
 <li>One or more catheters, which are flexible plastic tubes that are about the size of spaghetti noodles. </li>
 <li>Dye that is visible by x-ray. </li>
 <li>An x-ray machine. </li>
</ul>
During the procedure you'll lie down on a table underneath the x-ray machine. You may receive a mild sedative for relaxation. And the area where the catheter is to be inserted&mdash;either the arm, neck or groin&mdash;will be numbed with a local anesthetic. 
Once the anesthetic takes effect, the doctor will make a small incision and insert the IV line into a blood vessel. The doctor will insert the catheter through the IV and into the blood vessel, then guide it slowly into the heart with the help of x-ray imaging. 
Once the catheter reaches the area your doctor wants to examine, he or she will inject the dye and take an x-ray&mdash;this is called an angiogram. The resulting images of your heart and its chambers and arteries can be seen on a screen, and pictures can be taken for analysis. 
Goals of cardiac catheterization 
Cardiac catheterization can help show whether the arteries in your heart are blocked or narrowed by atherosclerosis, also called coronary artery disease. When arteries are known to be narrowed by atherosclerosis, the catheter might be tipped with a balloon that is inflated inside the arterial wall, opening the blockage&mdash;this is called angioplasty. The catheter can also be used to place a mesh stent inside an artery to help keep it open. 
Cardiac catheterization can also reveal structural defects and measure blood pressure and flow in the heart's chambers. 
The procedure is even used in infants who are suspected to have congenital heart abnormalities. 
What are the risks? 
Risks from cardiac catheterization range from injury to a blood vessel to stroke or heart attack. Sometimes people have an allergic reaction to the dye. 
The risks are higher in people who are older and in those who have certain chronic conditions like diabetes or kidney disease.
Talk to your doctor 
If your doctor has recommended cardiac catheterization, ask him or her to explain the benefits and risks specific to your health. 
Reviewed 7/11/2023

A guide to cardiac catheterization

Cardiac catheterization can help doctors find, treat or rule out problems with the heart.