Cardiac Catheterization

Cardiac catheterization is a specialized procedure in which a long, flexible tube — a catheter — is inserted into a vein or artery and guided into the heart.

• It’s often used instead of open-heart surgery to treat congenital heart defects.
• Boston Children’s performs hundreds of cardiac catheterizations a year.
• Boston Children’s trains more specialists in performing the procedure than any other hospital in the United States.

Cardiac catheterization is often used to treat congenital heart defects on babies and small children for whom open-heart surgery may be very risky. It can even be performed on babies immediately after birth.

Cardiac catheterization may be performed for the following reasons:

• to perform valvuloplasties or angioplasties by inflating balloons in obstructed valves or vessels
• to obtain cardiac tissue samples for biopsy
• to open the atrial septum to alleviate certain types of congenital heart defects that cause an infant to become cyanotic (blue skin, lips and nail beds due to an insufficient supply of oxygen in the blood)
• to place devices that close small holes inside the heart (such as with atrial septal defect or ventricular septal defect), or intentionally block blood flow in a blood vessel
• to place wire devices, called stents, in narrowed blood vessels to keep them open
• to conduct an electrophysiologic study (EPS) or a radiofrequency catheter ablation (RFCA) procedure, which identifies the site of an arrhythmia's origin within the heart tissue (in many cases this procedure can eliminate the arrhythmia)

A specially trained cardiologist performs the procedure.

Some catheterizations are performed on an outpatient basis (the patient arrives in the morning for the procedure, and may be able to go home in the afternoon or evening). Your cardiologist will tell you whether an outpatient procedure is appropriate for you, and give details on how to prepare for a heart cath.

Your child is given a sedative to help her relax and sleep during the procedure.

In the "cath lab,” your child will lie on a small table with a c-shaped x-ray machine. Heart monitors and other equipment are nearby. A specially trained staff of nurses, technicians, and physicians monitor your child and make sure she is comfortable during the procedure.

• Step 1: Your child receives an injection of local anesthetic in the spot where the catheter will be inserted. Next, a thin, flexible tube (catheter) is inserted into a blood vessel, most often in the groin area.
• Step 2: The cardiologist uses x-rays, called fluoroscopy, to help visualize the movement of the catheter as it makes its way up the vein toward the right atrium. Eventually, the tube is guided into the right ventricle, the pulmonary artery, and perhaps the right and/or left pulmonary artery branches.
• Step 3: While inside the heart, several things are done to help evaluate the heart structures, as well as the pattern of blood flow:
  • Blood samples are drawn from a number of vessels and heart chambers, which will allow for calculation of heart function and flow characteristics.
  • Blood pressure measurements are taken.
  • A contrast fluid is injected into the catheter and, as it flows inside the heart, x-ray films are made of the path the fluid takes throughout the heart.

The catheter is withdrawn and several gauze pads are placed on the site to prevent bleeding. If the blood vessels in the leg were used as the insertion site, your child will be told to keep her leg straight for a few hours after the procedure to minimize the chance of bleeding.

Your child is then taken to a unit in the hospital where she will be monitored by nursing staff for several hours after the test. You will receive written instructions regarding care of the catheterization site, bathing, activity restrictions, and any new medications your child may need to take at home.

Depending on the results of the cardiac catheterization test, additional tests or procedures may be scheduled to gather further diagnostic information.

Boston Children’s interventional catheterization specialists use catheterization to observe a fetus or child’s heart structure, measure blood pressure, close holes, expand narrowed passages, and open new passages. The procedure is now used in instances that once required surgery.