The procedure is performed in the hospital by a specially trained cardiologist. A child is given a sedative to help them relax and possibly even sleep during the procedure. Once in the "cath lab," they lay on a small table with a C-shaped x-ray machine surrounding it and heart monitors nearby. A specially trained staff of nurses, technicians and physicians monitor the child and makes sure they are comfortable during the procedure.
An injection of local anesthetic is given under the skin where the catheter is to be inserted. Next, a thin, flexible tube (catheter) is inserted into a blood vessel, most often in the groin area (the crease of the leg where it bends when sitting).
The catheter is guided up the vessel towards the heart. The cardiologist uses x-rays to help visualize the movement of the catheter. For example, the catheter enters the right atrium (the top right-hand chamber that receives oxygen-poor (blue) blood from the body). Eventually, the tube is guided into the right ventricle, the pulmonary artery and perhaps the right and/or left pulmonary artery branches.
While the catheter is inside the heart, several things are done to help evaluate the structure — as well as the pattern of blood flow — inside the heart. Blood samples are drawn and blood pressure measurements are taken from each chamber and blood vessel. Contrast dye is injected into the catheter and, as it flows inside the heart, x-ray films are made of the path the dye takes. X-ray films are made as the catheterization proceeds, enabling your child's cardiologist to review the data after the procedure. If surgery is planned, the heart surgeon may also review the data.