Like the Norwood surgery post, this post is intended primarily to explain what a cardiac catheterization is in general terms as well as explain how it went for Lillian. There will be a follow up post with the surgeon's notes later. As before, this will be much easier to follow if you've familiarized yourself with Lillian's heart condition, which you can read about here, as well as (to a lesser extent) her first surgery, which you can read about here.
A cardiac catheterization is a minimally invasive surgical procedure that allows the catherterization doctor/surgeon very clear views of the patient's heart and blood flow; in addition to allowing for other procedures like angioplasties. The way they are able to view the heart is by taking special X-rays called angiograms that allow extremely clear images of the heart. One such image is seen above. The procedure starts with surgeon inserting a guide wire into either the femoral artery (in the groin) or the radial artery (in the wrist). The surgeon then guides a plastic sheath over the guide wire and removes the guide wire once the sheath is in place. This sheath allows for the insertion of the cathether which is guided through the artery to the heart using another guide wire and X-rays. Once it reaches the intended location, the surgeon can inject special dye that is visible to X-rays or perform other procedures.