a cramp in the heart. exactly what the president was describing. a sense of discomfort. a sense of tightness. a sense of pressure. so it's just as he developed, as this graft closed and he became dependent again on the clogged up artery, his heart was not getting enough blood with even minimal exercise. >> how major a procedure was what the president underwent today? we heard his physician say that it was about an hour-long operation, but what actually happens and how hard a thing is it to endure? >> so it's not difficult to endure. it's a procedure that has to be taken very seriously, though. i describe it as doing a bypass from outside the body. so basically what we do is to bring the patient into what looks like an operating room, but it's a sterile environment with x-ray and under local anesthesia we make a tiny -- place a needle into the big