A cardiac catheterization (heart catheterization) is a procedure used to diagnose and treat certain heart conditions.
A long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin, or neck and threaded to your heart. Through the catheter, cardiologists can do diagnostic tests and treatments on your heart.
For example, your cardiologist may put a special dye in the catheter. This dye will flow through your bloodstream to your heart. Once the dye reaches your heart, it will make the inside of your coronary (heart) arteries show up on an x ray. This test is called coronary angiography.
The dye can show whether a substance called plaque has narrowed or blocked any of your coronary arteries. Plaque is made up of fat, cholesterol, calcium, and other substances found in your blood.
Plaque narrows the inside of the arteries and, in time, may restrict blood flow to your heart. When plaque builds up in the coronary arteries, the condition is called coronary artery disease (CAD) or coronary artery disease.
Blockages in the coronary arteries also can be seen using ultrasound during cardiac catheterization. Ultrasound uses sound waves to create detailed pictures of the heart's blood vessels.
Cardiologists usually do cardiac catheterization in a hospital. You're awake during the procedure, and it causes little to no pain. However, you may feel some soreness in the blood vessel where the catheter was inserted. Cardiac catheterization rarely causes serious complications.