How is an ASD closed using a catheter-based procedure ?Catheter-based procedures are commonly used to diagnose and treat heart-related problems. For example, catheter-based procedures are used to diagnose and treat clogged arteries and heart attacks. A catheter can also be used to guide the placement of an ASD device - which becomes a permanent implant - that will close the hole in the heart wall. To further briefly explain what happens in an ASD catheter-based procedure, a cardiac catheterization involves slowly moving a catheter (a long, thin, flexible, hollow tube) into the heart. The catheter is initially inserted into a large vein through a small incision made usually in the inner thigh (groin area) and then is advanced to and into the heart. One or more tests will be done to measure the ASD and to be sure there are no other defects. An imaging test called angiography, (an injection of a certain type of dye followed by an x-ray motion picture) may be used to better visualize the heart. An ultrasound imaging technique, to see the defect better and also to determine the size of the closure device needed, may be used. One technique, intracardiac echo (ICE), involves passing an imaging device up to the heart through the vein in the patient’s other leg. Another technique uses an ultrasound probe passed down the esophagus (transesophageal echo, or TEE) to allow your doctor to see the heart structures and blood flow as the device is being placed. In addition, a special balloon on a catheter is moved to the area of the hole and inflated across the hole in order to measure the size of the hole when it is gently stretched. An ASD closure device is moved through the catheter to the heart and specifically to the location of the heart wall defect. Once in the correct location, the ASD closure device is allowed to expand its shape to straddle each side of the hole. The device will remain in the heart permanently to stop the abnormal flow of blood between the two atria chambers of the heart. The catheter is then removed and the procedure is complete.