Exam Overview

A heart catheterization is a procedure used for both diagnosis and treatment of congenital heart defects. The procedure allows health professionals to see how blood flows through the heart chambers and arteries. This test may also be called angiography (angiogram), cardiac catheterization, or heart cath.

To perform a heart catheterization, a thin, flexible tube called a catheter is threaded through a blood vessel in the groin, or sometimes in another location, and into the heart. Through the catheter, the doctor can measure pressures, take blood samples, and inject a special dye (contrast material) into the chambers of the heart or the coronary arteries. The doctor watches the movement of the dye through the heart's chambers and blood vessels.

A heart catheterization can be used to:

• See whether the structure (anatomy) of the heart is normal.
• Measure pressures in the heart chambers and see how the blood is flowing through the heart.
• Collect samples of blood from inside the heart.
• Inject a dye into the heart or arteries to see whether there are abnormal blockages in the blood vessels or abnormalities of the heart chambers (such as defects or holes between chambers).
• View and correct certain heart defects.

A heart catheterization usually takes between 2 and 3 hours to complete. After the test, pressure must be applied over the catheter site for 10 to 20 minutes to stop bleeding and bruising. Then a large bandage is used to apply pressure to the catheter site for 4 to 6 hours.

Why It Is Done

The main purpose of a heart catheterization is to view the condition of the blood vessels in the heart.

Some procedures to correct congenital heart defects can be done during a heart catheterization. These include:

• Septostomy. For a septostomy, an opening is made in the wall of the heart between the upper chambers to allow blood to mix between the heart chambers. This procedure is generally used to treat transposition of the great vessels, tricuspid atresia, and hypoplastic left heart syndrome. It does not correct the congenital heart defect but allows oxygen-rich blood to get out to the body until surgery can be done to correct the defect.
• Closing a defect. During a heart catheterization, doctors may use a device called a septal occluder or coil to close an atrial septal defect, ventricular septal defect, or patent ductus arteriosus.
• Balloon valvuloplasty. For a balloon valvuloplasty, a small balloon is inflated in a heart valve, widening the heart valve. This procedure can be used to treat pulmonary valve stenosis and aortic valve stenosis.
• Balloon angioplasty. A balloon is inflated in an artery to widen the artery. This procedure can be used to treat coarctation of the aorta.
• Stents. Small wire-mesh coils (stents) can be placed in arteries to hold them open. Stents for treatment of congenital heart defects are often placed in arteries outside the heart, such as the pulmonary arteries or aorta.

Results

In a child who has a congenital heart defect, a heart catheterization shows how the blood is flowing through the heart. The exact heart problem can be seen and sometimes treated during the same procedure or a later procedure.

What To Think About

Major problems very rarely occur in people who have a heart catheterization. These problems can include:

• Irregular heartbeats (arrhythmias).
• Puncture of the heart muscle or a blood vessel.
• Problems where the catheter was inserted, such as a blood clot, a blocked artery, or an infection.
• Allergy to the X-ray dye (allergic reactions may range from mild itching to life-threatening situations).
• Death from bleeding, blood clots, or an allergic reaction.

Before the test, your child receives medicine to make him or her relax and sleep—sedatives or sometimes general anesthesia. After the test, your child will need to lie still for 5 to 8 hours and keep the leg in which the catheter was inserted straight to prevent bleeding. You may need to hold your child in your lap after the test to prevent leg movement, or your child can wear a leg board with a Velcro strap to hold the leg still.

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