The first coronary angiograms were done in 1958. However, it also is scary to think about having your heart worked on, and most people who are told they need to have this procedure are understandably concerned. The animation above illustrates a cardiac catheterization. The patient is generally sedated to some degree.
Local anesthetic is used to numb the area over the blood vessels.
The catheters are advanced through the large vessels to the heart with the aid of x-rays. Since the blood vessels do not have pain fibers, the catheters are not felt as they are moved through the blood vessels. Pressures are measured in various chambers of the heart. This allows a picture to be made of the inside of the blood vessel with the aid of x-rays. You may also want to check out the links to other areas on HeartPoint which discuss the heart's function and anatomy for further insight and information.