Heart catheterization (heart cath) is a diagnostic procedure in which a catheter is inserted into the right or left chambers or vessels of the heart.

A heart catheterization procedure allows the physician to investigate and locate heart disease. In some cases, a cardiologist will perform a minimally-invasive procedure known as a percutaneous coronary intervention (PCI) or angioplasty to open clogged arteries by using a balloon and/or stent.

A heart catheterization may be performed to diagnose and evaluate:

• Coronary artery disease
• Congenital heart defects
• Problems with heart valves
• Causes of heart failure or cardiomyopathy 
• Certain types of heart defects
• A stuck (stenotic) heart valve
• Open blocked arteries or grafts.

How the Test is Performed

Prior to the test, the patient will receive a mild sedative. The patient's arm, neck or groin is cleansed and numbed before an intravenous (IV) line is inserted. The catheter is inserted through the IV and threaded to the heart. Once the catheter is in place, a cardiologist can:

• Collect blood samples
• Measure pressure and blood flow in the chambers and large arteries
• Measure the oxygen levels
• Examine the arteries using an X-ray technique, fluoroscopy, which provides real-time images
• Perform a biopsy on the heart muscle

How to Prepare for the Test

If possible, the patient should not eat or drink six to eight hours prior to the procedure. The test will take place in the hospital, and in some cases, the patient will be required to stay overnight. Patients should tell his/her physician if they:

• Are allergic to seafood
• Had a bad reaction to contrast material or iodine
• Are taking Viagra
• Might be pregnant

What the Risks are

Risks of a heart catheterization procedure are slightly higher than other heart tests, however, the procedure is safe. Risks of heart catheterization may include:

• Cardiac arrhythmias
• Cardiac tamponade
• Heart attack
• Bleeding
• Low blood pressure
• Reaction to the contrast medium
• Stroke
• Trauma to the artery caused by hematoma